Modal verbs “can” và “could” là hai động từ khiếm khuyết xuất hiện thường xuyên trong tất cả các phần thi IELTS. Hai modal verbs này có chức năng biểu đạt khả năng, khả thi, xin phép, yêu cầu, và đưa ra gợi ý – những tình huống giao tiếp rất phổ biến trong kỳ thi IELTS. Theo phân tích từ Cambridge IELTS 10-19, “can” và “could” xuất hiện với tần suất cao trong:
- Speaking: Part 1, 2 và 3 (mô tả khả năng, đưa ra gợi ý, thảo luận khả thi)
- Writing Task 2: Đưa ra giải pháp, thảo luận khả năng thực hiện
- Writing Task 1: Mô tả xu hướng có thể xảy ra (dự đoán)
Ví dụ vận dụng trong IELTS:
Speaking Part 2 (Describe a skill):
“I can speak three languages fluently, which has helped me communicate with people from different cultures.”
→ Phân tích: [Subject] + [can] + [bare infinitive] – biểu đạt khả năng hiện tại
Writing Task 2 (Solution essay):
“Governments could invest more in renewable energy to reduce carbon emissions.”
→ Phân tích: [Subject] + [could] + [bare infinitive] – đưa ra gợi ý/giải pháp
Speaking Part 3 (Giving opinion):
“Technology could potentially replace many traditional jobs in the future.”
→ Phân tích: [Subject] + [could] + [adverb] + [bare infinitive] – biểu đạt khả năng trong tương lai
Writing Task 2 (Discussion):
“While some people can adapt quickly to changes, others cannot cope with rapid transformation.”
→ Phân tích: Đối chiếu [can] và [cannot] để thể hiện sự khác biệt
Speaking Part 1 (Personal questions):
“When I was younger, I couldn’t swim, but now I can swim quite well.”
→ Phân tích: Sử dụng [could/couldn’t] cho quá khứ và [can] cho hiện tại
Trong bài viết này, bạn sẽ học:
✅ Định nghĩa và ý nghĩa của can và could
✅ Công thức chi tiết với các chức năng khác nhau
✅ Cách vận dụng vào 4 kỹ năng IELTS
✅ 25+ câu ví dụ Band 7-9
✅ Các biến thể nâng cao cho Band 8+
✅ Lỗi thường gặp của học viên Việt Nam
✅ Bài tập thực hành có đáp án chi tiết
Modal Verbs Can và Could Là Gì?
Định Nghĩa
Can và could là hai modal verbs (động từ khiếm khuyết) được sử dụng để biểu đạt nhiều chức năng khác nhau trong tiếng Anh. “Can” chủ yếu dùng cho hiện tại và tương lai, trong khi “could” là dạng quá khứ của “can” nhưng cũng có nhiều chức năng khác không liên quan đến thời gian.
Chức năng chính:
- Khả năng (Ability): Diễn tả ai đó có thể làm gì
- Khả thi (Possibility): Nói về điều gì có thể xảy ra
- Xin phép (Permission): Xin hoặc cho phép làm điều gì
- Yêu cầu (Request): Đề nghị ai đó làm gì
- Gợi ý (Suggestion): Đưa ra ý kiến hoặc đề xuất
Khi nào dùng trong IELTS:
- Speaking: Mô tả kỹ năng cá nhân, đưa ra gợi ý giải quyết vấn đề, thảo luận khả năng xảy ra của sự kiện
- Writing: Đề xuất giải pháp, phân tích khả thi, đưa ra dự đoán có căn cứ
- Reading/Listening: Hiểu ý nghĩa chính xác trong ngữ cảnh (khả năng, khả thi, hay gợi ý)
Tần Suất Xuất Hiện Trong IELTS
Theo phân tích từ Cambridge IELTS 10-19:
Speaking:
- Part 1: Rất thường xuyên – Câu hỏi về sở thích, khả năng, thói quen (“Can you cook?”, “What languages can you speak?”)
- Part 2: Thường xuyên – Mô tả kỹ năng, kinh nghiệm, điều ước trong quá khứ
- Part 3: Rất thường xuyên – Thảo luận giải pháp, khả thi của ý tưởng, dự đoán xu hướng
Writing:
- Task 1: Trung bình – Dùng “can be seen”, “could indicate” khi phân tích biểu đồ
- Task 2: Rất thường xuyên – Đặc biệt quan trọng trong Problem-Solution và Discussion essays
Listening/Reading:
- Xuất hiện thường xuyên trong mọi dạng câu hỏi
- Cần phân biệt giữa khả năng thực tế và khả năng lý thuyết
- Quan trọng cho câu hỏi True/False/Not Given
Band Score Impact:
- Band 6: Sử dụng cơ bản “can” cho khả năng, có thể nhầm lẫn với các modal khác
- Band 7: Sử dụng cả “can” và “could” chính xác, phân biệt được các chức năng khác nhau
- Band 8-9: Sử dụng linh hoạt với các cấu trúc phức tạp, kết hợp với passive voice, perfect forms
Công Thức & Cấu Trúc
Công Thức Cơ Bản
📌 CÔNG THỨC CHÍNH:
┌─────────────────────────────────────────────┐
│ Subject + can/could + bare infinitive │
│ │
│ Ví dụ: She can speak five languages. │
└─────────────────────────────────────────────┘Thành phần câu:
- Subject (Chủ ngữ): Bất kỳ danh từ hoặc đại từ nào (I, you, he, she, it, we, they, people, students, etc.)
- Can/Could: Modal verb – không chia theo ngôi, không thêm “s” với ngôi thứ 3 số ít
- Bare infinitive: Động từ nguyên mẫu không “to” (go, speak, write, understand, etc.)
Ví dụ phân tích chi tiết:
Câu: “Young people can access information instantly through the internet.”
Phân tích:
- Subject: Young people (chủ ngữ số nhiều)
- Modal verb: can (biểu đạt khả năng hiện tại)
- Main verb: access (động từ nguyên mẫu không “to”)
- Object: information (tân ngữ)
- Adverb: instantly (trạng từ chỉ cách thức)
- Prepositional phrase: through the internet (cụm giới từ chỉ phương tiện)
Các Biến Thể
Dạng khẳng định:
-
Present/Future: Subject + can + bare infinitive
- “I can help you with your homework.”
- “Technology can solve many problems.”
-
Past: Subject + could + bare infinitive
- “When I was young, I could run very fast.”
- “In the past, people could not access information easily.”
Dạng phủ định:
-
Present/Future: Subject + cannot/can’t + bare infinitive
- “We cannot ignore environmental issues.”
- “Many people can’t afford expensive healthcare.”
-
Past: Subject + could not/couldn’t + bare infinitive
- “She couldn’t attend the meeting yesterday.”
- “Students couldn’t use calculators during the exam.”
Dạng nghi vấn:
-
Present/Future: Can + subject + bare infinitive?
- “Can you explain this grammar point?”
- “Can governments reduce unemployment?”
-
Past: Could + subject + bare infinitive?
- “Could you understand the lecture?”
- “Could people predict this crisis?”
Dạng nhấn mạnh với “be able to”:
- “I am able to work under pressure.” (tương đương “can” nhưng formal hơn)
- “She was able to complete the project on time.” (nhấn mạnh thành công trong tình huống cụ thể)
Signal Words & Context Indicators
Các từ/cụm từ thường đi kèm Can/Could:
| Signal Words | Ý nghĩa | Ví dụ |
|---|---|---|
| easily | một cách dễ dàng | “People can easily communicate via social media.” |
| possibly/potentially | có khả năng | “This solution could potentially reduce pollution.” |
| no longer | không còn nữa | “We can no longer ignore climate change.” |
| if + present simple | điều kiện | “If we act now, we can prevent further damage.” |
| in the future | trong tương lai | “Technology could replace many jobs in the future.” |
| nowadays/today | ngày nay | “Students can access online courses nowadays.” |
| in the past | trong quá khứ | “People couldn’t travel as easily in the past.” |
| with + noun | với sự hỗ trợ của | “With proper training, employees can improve skills.” |
Sơ đồ phân biệt cách dùng Modal Verbs Can và Could trong các tình huống giao tiếp IELTS thường gặp
Cách Vận Dụng Vào IELTS
Speaking
Part 1 – Introduction & Interview:
Topic thường gặp: Hobbies, Skills, Daily routines, Languages, Technology
Ví dụ câu hỏi & trả lời:
Q: “Can you cook?”
A: “Yes, I can cook quite well. I learned from my mother when I was a teenager, and now I can prepare various Vietnamese dishes. However, I can’t make Western food because I’ve never really tried.”
→ Phân tích: Sử dụng “can” để mô tả khả năng hiện tại, “can’t” để chỉ hạn chế. Câu trả lời tự nhiên, có ví dụ cụ thể (Band 7+)
Q: “What languages can you speak?”
A: “I can speak Vietnamese fluently as it’s my mother tongue, and I can also communicate in English fairly well. When I was in primary school, I could speak a little French, but I can’t remember much now because I haven’t practiced for years.”
→ Phân tích: Kết hợp “can” (hiện tại) và “could” (quá khứ) để tạo timeline rõ ràng, thêm lý do giải thích (Band 7.5+)
Q: “Do you think everyone can learn to play a musical instrument?”
A: “I believe most people can learn if they’re dedicated and practice regularly. However, not everyone can become professional musicians because natural talent plays a role. That said, anyone can enjoy music and improve their skills with proper guidance.”
→ Phân tích: Sử dụng “can” để thể hiện quan điểm cân bằng, có sự phân biệt giữa khả năng học và khả năng trở thành chuyên nghiệp (Band 8+)
Part 2 – Long Turn:
Cue card example:
Describe a skill you would like to learn.
You should say:
- What skill it is
- Why you want to learn it
- How you could learn it
- And explain how this skill could benefit you
Sample answer (Band 8.0):
“I’d like to talk about public speaking, which is a skill I’m eager to develop. Currently, I can communicate well in one-on-one situations, but I can’t speak confidently in front of large audiences.
I want to learn this skill because I believe it could significantly enhance my career prospects. In today’s competitive job market, professionals who can present ideas effectively often advance faster than those who can’t. Moreover, strong public speakers can influence others and inspire change, which is something I find incredibly valuable.
To develop this ability, I could join a local Toastmasters club, where members practice speaking in a supportive environment. I could also watch TED talks and analyze how experienced speakers engage their audiences. Additionally, I could record myself practicing and identify areas for improvement.
This skill could benefit me in numerous ways. Professionally, I could pitch ideas to clients more convincingly and lead meetings with greater authority. Personally, it could boost my self-confidence and help me network more effectively. In the long run, I believe strong communication skills can open doors that might otherwise remain closed.”
→ Phân tích Band 8.0:
- Sử dụng đa dạng: “can” (khả năng hiện tại), “can’t” (hạn chế), “could” (khả thi/lợi ích tương lai)
- Cấu trúc phức: “professionals who can present…” (relative clause)
- Từ vựng học thuật: enhance, prospects, influence, authority
- Luồng ý logic, có ví dụ cụ thể
Part 3 – Discussion:
Typical questions using can/could:
Q: “How can governments encourage people to use public transportation?”
A: “There are several effective strategies governments could implement. First, they could reduce ticket prices or offer free travel during peak pollution days. This can make public transport more attractive than driving. Second, authorities could invest in infrastructure improvements – better buses and trains can provide a more comfortable experience. They could also create dedicated bus lanes so that public transport can move faster than private vehicles during rush hours. Additionally, governments can launch awareness campaigns to educate people about environmental benefits. If these measures are combined, I believe they could significantly increase public transport usage.”
→ Band 8+ features: Variety của “can” và “could”, cấu trúc điều kiện, liên kết logic, giải pháp chi tiết và thực tế
Q: “Do you think technology can replace teachers in the future?”
A: “While technology can certainly enhance education, I don’t believe it could completely replace human teachers. AI and online platforms can deliver content efficiently and can adapt to individual learning speeds, which is beneficial. However, teachers can provide emotional support and mentorship that technology cannot replicate. They can read students’ body language, sense when someone is struggling, and offer personalized encouragement. Young children, especially, need human interaction that computers could never fully provide. So, technology and teachers could work together, but one cannot substitute for the other entirely.”
→ Band 9 features: Balanced argument, sử dụng “can” và “cannot/could never” để tạo contrast, sophisticated vocabulary (replicate, mentorship), natural flow
Writing Task 1
Khi nào dùng:
- Mô tả xu hướng có thể quan sát được
- Đưa ra nhận xét về ý nghĩa của dữ liệu
- So sánh khả năng giữa các nhóm dữ liệu
Ví dụ:
Bar chart showing internet usage by age groups
Opening statement:
“The bar chart illustrates how internet usage varies across different age groups, from which several trends can be observed.”
→ Vận dụng: “Can be observed” là cụm academic phổ biến trong Task 1
Body paragraph:
“It can be seen that younger demographics use the internet far more frequently than older age groups. People aged 18-30 can access the internet for an average of 6 hours daily, while those over 65 can only manage approximately 1 hour. This disparity could be attributed to differences in digital literacy and technological familiarity.”
→ Vận dụng:
- “It can be seen that” – cụm mở đầu formal
- “Can access/can only” – mô tả khả năng thực tế
- “Could be attributed to” – đưa ra giải thích có căn cứ (Band 8+)
Line graph showing predicted trends:
“Based on current trajectories, internet penetration could reach 95% by 2030. However, rural areas cannot be expected to achieve the same growth rate as urban centers due to infrastructure limitations.”
→ Vận dụng: Dùng “could” cho dự đoán có cơ sở, “cannot be expected” cho điều không khả thi (Band 8+)
Writing Task 2
Essay types sử dụng can/could:
Problem-Solution Essay:
Topic: Environmental pollution is increasing. What are the causes and what solutions can individuals and governments implement?
Problem paragraph:
“Industrial activities can release toxic chemicals into water sources, which can contaminate drinking water and harm aquatic ecosystems. Additionally, vehicle emissions cannot be absorbed quickly enough by natural processes, leading to air quality deterioration. These pollutants can cause serious health issues such as respiratory diseases and cancer.”
→ Phân tích: “Can” biểu thị khả năng thực sự gây hại, “cannot be absorbed” chỉ hạn chế của tự nhiên
Solution paragraph (Band 8.0):
“To address these issues, both individuals and governments can take decisive action. At the individual level, people can reduce their carbon footprint by using public transportation, which can significantly decrease the number of vehicles on roads. They can also adopt a minimalist lifestyle and avoid single-use plastics. However, individual efforts alone cannot solve the problem entirely.
Governments could introduce stricter environmental regulations that force companies to reduce emissions. They could invest in renewable energy infrastructure, which can provide clean alternatives to fossil fuels. Furthermore, authorities could offer tax incentives to businesses that adopt eco-friendly practices. If these measures are implemented effectively, we could see substantial environmental improvements within a decade.”
→ Phân tích Band 8.0:
- Đa dạng: “can take/reduce/decrease” (khả năng thực tế), “could introduce/invest” (đề xuất)
- Logic: Phân biệt rõ cá nhân vs chính phủ
- Academic: “cannot solve… entirely”, “could see substantial improvements”
- Cohesion: “However”, “Furthermore”, “If these measures…”
Opinion Essay:
Topic: Some people believe that university education should be free for all students. To what extent do you agree or disagree?
Body paragraph (Band 8.5):
“Free university education could provide equal opportunities for talented students from disadvantaged backgrounds who cannot afford tuition fees. These individuals can contribute significantly to society if given the chance, as intelligence and potential are not determined by wealth. Countries like Germany and Norway have demonstrated that free higher education can work successfully without compromising quality.
However, implementing such a policy cannot be straightforward. Governments can face enormous financial burdens, particularly in developing nations where budgets are already stretched. Free education could also lead to overcrowding in universities, which can diminish the quality of teaching and resources. Moreover, when education is free, some students cannot appreciate its value and may not take their studies seriously.
A more balanced approach could be to offer means-tested scholarships. This system can ensure that those who genuinely need financial support receive it, while those who can afford tuition continue to pay. Such a model can maintain funding levels while promoting equality.”
→ Phân tích Band 8.5:
- Balanced argument với nhiều ý sử dụng “can/could”
- Advanced: “cannot be straightforward”, “could lead to”, “can ensure”
- Cohesion: “However”, “Moreover”, “A more balanced approach”
- Paraphrasing: “can work” vs “can be successful”
Advantage-Disadvantage Essay:
Topic: Online shopping is becoming increasingly popular. What are the advantages and disadvantages?
Advantages paragraph:
“One major benefit is convenience – consumers can purchase products at any time without leaving their homes. This can save considerable time, especially for busy professionals who cannot visit physical stores during business hours. Additionally, online platforms can offer lower prices because they can reduce overhead costs associated with maintaining brick-and-mortar locations.”
Disadvantages paragraph:
“However, shoppers cannot physically examine products before purchase, which can lead to disappointment when items don’t meet expectations. Returns can be complicated and time-consuming. Moreover, online shopping can encourage impulsive buying – the ease of clicking ‘buy now’ means people cannot resist temptation as easily as when they can see their wallets emptying.”
→ Phân tích: Sử dụng “can/cannot” để liệt kê advantages (can do X) và disadvantages (cannot do Y) một cách cân đối
Ví dụ đoạn văn Writing Task 2 sử dụng Can và Could đạt Band 8.0 với phân tích chi tiết
Sample Paragraphs Band 7-9
Band 7 Sample – Discussion Essay:
Topic: Should countries prioritize economic growth or environmental protection?
“Economic development and environmental conservation are both important, and countries can pursue both objectives simultaneously. Governments can invest in green technologies that create jobs while protecting nature. For example, renewable energy projects can generate employment opportunities and reduce carbon emissions at the same time. However, if nations focus only on economic growth, they cannot avoid environmental degradation, which can harm future generations. Therefore, a balanced approach can be the most effective solution.”
Phân tích:
- Sử dụng “can” chính xác trong nhiều contexts
- Variety: “can pursue”, “can invest”, “can generate”, “cannot avoid”, “can harm”, “can be”
- Structure đơn giản nhưng hiệu quả
- Có ví dụ cụ thể (renewable energy)
- Điểm yếu: Chưa có cấu trúc phức, chưa dùng “could” cho suggestion
Band 8-9 Sample – Problem-Solution Essay:
Topic: Youth unemployment is rising in many countries. What are the causes and solutions?
“Youth unemployment has emerged as a pressing challenge that modern societies cannot afford to ignore. One fundamental cause is the mismatch between educational curricula and job market requirements – universities often produce graduates who cannot meet employers’ demands for practical skills. Additionally, economic recessions can disproportionately affect young job seekers, as companies facing financial constraints cannot justify hiring inexperienced workers when they can recruit veterans instead.
To address this multifaceted problem, educational institutions could overhaul their programs to emphasize vocational training and internships, enabling students to acquire skills that can translate directly into employment. Such reforms could bridge the gap between theoretical knowledge and workplace reality. Simultaneously, governments could incentivize businesses to hire young workers through tax breaks and subsidies. While these measures alone cannot eradicate unemployment entirely, they could significantly alleviate the crisis if implemented systematically.
Moreover, young people themselves can take proactive steps to enhance their employability. They could pursue online certifications, volunteer to gain experience, and develop soft skills that employers value. Although individuals cannot control macroeconomic factors, they can influence their own career trajectories through continuous learning and adaptability.”
Phân tích Band 9:
- Complex usage: “cannot afford to ignore”, “could overhaul”, “can translate directly”
- Natural flow: Sử dụng can/could một cách tự nhiên, không forced
- Range: Variety giữa present (can), conditional (could), negative (cannot)
- Academic collocations: “cannot justify”, “could bridge the gap”, “could significantly alleviate”
- Sophisticated structures: Participle phrases, relative clauses kết hợp với modals
- Cohesion: “Additionally”, “Simultaneously”, “Moreover” tạo liên kết mạch lạc
Nâng Cao – Cách Dùng Để Đạt Band 8+
Kết Hợp Với Các Cấu Trúc Khác
Can/Could + Relative Clause:
Example: “Students who can demonstrate creativity and critical thinking can secure better job opportunities than those who cannot.”
→ Band 8+ features: Relative clause làm rõ subject, contrast giữa “can” và “cannot”
Example: “Environmental policies that could reduce emissions by 30%, which can be achieved through renewable energy, should be prioritized.”
→ Sophistication: Non-defining relative clause bổ sung thông tin, passive voice với “can”
Can/Could + Perfect Infinitive (have + past participle):
Example: “The accident could have been prevented if proper safety measures had been implemented.”
→ Advanced usage: Chỉ khả năng trong quá khứ không xảy ra (unreal past)
Example: “She cannot have forgotten the meeting – I reminded her this morning.”
→ Band 9: Dùng để suy luận về quá khứ (deduction)
Example: “Technology could have transformed education earlier, but traditional institutions resisted change.”
→ Sophistication: Phê phán điều đã không xảy ra trong quá khứ
Can/Could + Passive Voice:
Example: “Significant improvements in air quality can be achieved if governments enforce stricter regulations.”
→ Academic style: Passive voice tập trung vào hành động, không phải actor
Example: “This problem cannot be solved by individuals alone; collective action is required.”
→ Band 8+: Nhấn mạnh impossibility bằng passive
Example: “Alternative solutions could be explored to address this multifaceted issue.”
→ Formal suggestion: Dùng trong Writing Task 2 conclusion
Can/Could + Continuous Form:
Example: “At this very moment, thousands of people could be suffering from preventable diseases.”
→ Advanced: Nhấn mạnh hành động đang diễn ra (possibility)
Example: “Climate change can be affecting ecosystems in ways we don’t fully understand yet.”
→ Sophistication: Ongoing possibility
Cụm Từ Nâng Cao
Academic collocations with can/could:
| Collocation | Ví dụ | Band Level |
|---|---|---|
| can be attributed to | “This trend can be attributed to technological advancements.” | 7+ |
| could potentially lead to | “Such policies could potentially lead to economic growth.” | 7.5+ |
| cannot be underestimated | “The impact of education cannot be underestimated.” | 8+ |
| can be deemed | “This approach can be deemed effective based on evidence.” | 8+ |
| could arguably be | “This could arguably be the most significant development.” | 8+ |
| cannot afford to | “Society cannot afford to ignore mental health issues.” | 8+ |
| can ill afford | “Developing nations can ill afford to invest in space exploration.” | 8.5+ |
| could well be | “This could well be a turning point in climate policy.” | 8.5+ |
| cannot help but | “One cannot help but notice the stark inequality.” | 9 |
| can scarcely be | “The importance of this discovery can scarcely be overstated.” | 9 |
Complex phrases for Writing Task 2:
Expressing possibility with caution:
- “While it could be argued that… this view overlooks…”
- “Although this approach can work in theory, practical implementation presents challenges.”
- “One cannot deny that… however…”
Example paragraph:
“While it could be argued that stricter laws deter crime, this view overlooks underlying social factors. Poverty and lack of education can be more significant contributors to criminal behavior than weak legislation. Therefore, governments cannot afford to focus solely on punishment; they must address root causes that could potentially lead to lasting solutions.”
Câu Phức & Ghép
Tích hợp vào câu phức:
Example 1: “Although technology can provide unprecedented access to information, it cannot replace the critical thinking skills that educators develop in students, which can only be cultivated through human interaction and mentorship.”
→ Phân tích:
- Contrast với “although”: can provide vs cannot replace
- Relative clause: “which can only be”
- Complex idea với multiple clauses
Example 2: “If governments could invest more in preventive healthcare, which research shows can reduce long-term medical costs, nations could save billions while improving citizens’ quality of life.”
→ Sophisticated integration:
- Conditional: “If… could invest”
- Non-defining relative clause: “which research shows can reduce”
- Result clause: “could save”
- Cohesion từ nhiều layers
Example 3: “Not only can renewable energy reduce carbon emissions, but it can also create thousands of jobs, which could transform economies that have traditionally relied on fossil fuels.”
→ Band 9 features:
- Inversion: “Not only can renewable energy”
- Multiple clauses với các chức năng khác nhau của can/could
- Complex reasoning
Example 4: “While critics argue that individuals cannot make significant environmental impact, the reality is that collective action can lead to substantial change, provided that governments can create the necessary infrastructure and incentives.”
→ Analysis:
- Concession: “critics argue… cannot”
- Counter-argument: “can lead to”
- Condition: “provided that… can create”
- Balanced, nuanced argument (Band 8.5+)
Các cấu trúc câu phức nâng cao sử dụng Can và Could để đạt Band 8.5-9.0 IELTS Writing
So Sánh Với Cấu Trúc Tương Tự
Can/Could vs Be Able To
| Tiêu chí | Can/Could | Be Able To |
|---|---|---|
| Công thức | Subject + can/could + bare infinitive | Subject + am/is/are/was/were + able to + infinitive |
| Ý nghĩa | Khả năng chung, khả thi | Khả năng cụ thể, thành công trong tình huống nhất định |
| Formality | Neutral, phổ biến | Formal hơn, academic |
| Dùng khi | Khả năng tổng quát, habit | Thành công cụ thể, future với will |
| Ví dụ | “I can speak French.” | “After months of practice, I was able to pass the exam.” |
| Perfect tenses | Không dùng được | “I have been able to improve my skills.” |
| IELTS context | Speaking tự nhiên hơn | Writing Task 2 formal hơn |
Khi nào dùng cấu trúc nào:
Dùng CAN/COULD khi:
- Nói về khả năng chung: “She can swim very well.”
- Possibility: “This could happen in the future.”
- Request: “Could you help me?”
- Speaking Part 1, 2 – tự nhiên hơn
Dùng BE ABLE TO khi:
- Nhấn mạnh thành công trong tình huống cụ thể: “Despite difficulties, he was able to complete the project.”
- Sau modal verbs khác: “You will be able to improve with practice.” (không dùng “will can”)
- Perfect tenses: “I have been able to develop new skills.”
- Writing Task 2 – formal tone
Example comparison:
- “Students can learn online.” (khả năng chung)
- “With proper equipment, students are able to learn effectively online.” (điều kiện cụ thể + formal)
Could vs Might/May
| Tiêu chí | Could | Might/May |
|---|---|---|
| Probability | 30-50% possibility | Might: 20-30%, May: 40-50% |
| Usage | Suggestion, possibility | Possibility only |
| Tone | Less certain | May (more formal), Might (less formal) |
| Ví dụ | “This could work.” (có thể hiệu quả) | “This might work.” (ít chắc chắn hơn) |
| IELTS | Task 2 suggestions | Task 1 tentative descriptions |
Example comparison:
- “Governments could increase taxes to fund healthcare.” (suggestion với possibility vừa phải)
- “Taxes might increase if the deficit continues.” (prediction ít chắc chắn)
- “This policy may lead to improvements.” (formal prediction)
Cannot vs Must Not
| Tiêu chí | Cannot | Must Not |
|---|---|---|
| Ý nghĩa | Không có khả năng, không thể | Bị cấm, không được phép |
| Công thức | Subject + cannot + bare infinitive | Subject + must not + bare infinitive |
| Ví dụ | “I cannot attend the meeting.” (không thể) | “You must not smoke here.” (bị cấm) |
| IELTS | Expressing inability | Rules, prohibitions |
Important distinction:
- “Students cannot submit late assignments.” (không có khả năng – hệ thống không cho phép)
- “Students must not submit late assignments.” (quy định cấm)
Lỗi Thường Gặp & Cách Sửa
Lỗi 1: Thêm “to” sau can/could
❌ SAI:
- “She can to speak three languages.”
- “Could you to help me with this?”
- “People cannot to access clean water.”
✅ ĐÚNG:
- “She can speak three languages.”
- “Could you help me with this?”
- “People cannot access clean water.”
Giải thích:
Modal verbs (can, could, will, would, should, must, may, might) luôn đi với động từ nguyên mẫu không “to” (bare infinitive). Đây là lỗi phổ biến nhất của học viên Việt Nam vì trong tiếng Việt không có quy tắc tương tự.
Lưu ý:
- Sau “be able to” có “to”: “She is able to speak…”
- Nhưng sau can/could không có “to”
- Cách nhớ: Modal + V1 (động từ nguyên mẫu không “to”)
Lỗi 2: Chia động từ can/could theo ngôi
❌ SAI:
- “She cans speak English fluently.”
- “He coulds have helped us.”
- “Technology cans solve many problems.”
✅ ĐÚNG:
- “She can speak English fluently.”
- “He could have helped us.”
- “Technology can solve many problems.”
Giải thích:
Modal verbs KHÔNG BAO GIỜ chia theo ngôi, nghĩa là không thêm “s” cho ngôi thứ 3 số ít (he/she/it). Lỗi này xuất phát từ việc học viên áp dụng quy tắc thêm “s/es” của động từ thường vào modal verbs.
Quy tắc:
- I/You/We/They can → He/She/It can (không phải “cans”)
- I/You/We/They could → He/She/It could (không phải “coulds”)
Lưu ý:
Điều này cũng áp dụng cho tất cả modal verbs: will, would, should, must, may, might – không chia theo ngôi.
Lỗi 3: Dùng sai thì với could
❌ SAI:
- “Yesterday, I could finished my homework.”
- “Last year, she could went to Japan.”
- “When I was young, I could to swimming very fast.”
✅ ĐÚNG:
- “Yesterday, I was able to finish my homework.” (hoặc “I finished my homework.”)
- “Last year, she was able to go to Japan.” (hoặc “she went to Japan.”)
- “When I was young, I could swim very fast.”
Giải thích:
- “Could” chỉ khả năng chung trong quá khứ: “I could swim” = Tôi có khả năng bơi (thường xuyên)
- Với thành công cụ thể trong quá khứ, dùng “was/were able to“: “Yesterday, I was able to solve the problem” = Hôm qua tôi đã giải quyết được (một lần cụ thể)
- Không dùng “could + past tense”: “could finished” ❌
So sánh:
- “When I was 10, I could run 5km.” (khả năng chung trong quá khứ) ✅
- “Yesterday, I was able to run 5km despite my injury.” (thành công cụ thể) ✅
- “Yesterday, I could run 5km.” (nghe kỳ – ngụ ý có khả năng nhưng chưa chắc đã làm)
Lưu ý:
Trong negative và question form, có thể dùng “couldn’t” cho cả hai trường hợp:
- “I couldn’t finish the task yesterday.” ✅
- “Couldn’t you solve the problem?” ✅
Lỗi 4: Nhầm lẫn can và could trong requests
❌ SAI (không sai ngữ pháp nhưng không phù hợp):
- “Can you give me that report?” (với sếp – quá informal)
- “Could you possibly maybe perhaps help me?” (quá nhiều từ redundant)
✅ ĐÚNG:
- “Could you give me that report?” (lịch sự hơn, phù hợp với sếp)
- “Could you help me with this?” (đủ lịch sự, không cần thêm từ)
Giải thích:
- “Can” = informal request, dùng với bạn bè, người quen
- “Could” = polite request, dùng trong IELTS Speaking, formal situations
- “Could you possibly” = very polite, nhưng không cần thêm “maybe”, “perhaps” (redundant)
Mức độ lịch sự (tăng dần):
- “Give me that.” (rude – không nên dùng)
- “Can you give me that?” (informal)
- “Could you give me that?” (polite)
- “Could you please give me that?” (very polite)
- “Would you mind giving me that?” (extremely polite)
IELTS Speaking:
- Part 1, 2: Có thể dùng “can” tự nhiên
- Part 3 hoặc khi role-play formal situation: Nên dùng “could”
Lỗi 5: Dùng can/could cho permission không phù hợp
❌ SAI (grammar đúng nhưng context sai):
- “Can I borrow your pen?” (IELTS Speaking Part 3 – quá informal cho discussion)
- “Students can leave early if they want.” (trong Task 2 discussing school rules – không formal)
✅ ĐÚNG:
- “May I borrow your pen?” (formal permission)
- “Students are allowed to/permitted to leave early if they have valid reasons.” (formal Writing Task 2)
Giải thích:
Trong IELTS Writing Task 2 và Speaking Part 3, khi nói về quy định, luật lệ, permission:
- Tránh: “can” (quá informal)
- Nên dùng: “be allowed to”, “be permitted to”, “have permission to”, “may” (formal)
Context matters:
- IELTS Speaking Part 1: “Can I talk about my hometown?” ✅ (tự nhiên)
- IELTS Writing Task 2: “Citizens are allowed to vote at 18.” ✅ (formal)
- IELTS Writing Task 2: “Citizens can vote at 18.” ⚠️ (không sai nhưng kém formal)
Lưu ý đặc biệt cho học viên Việt Nam:
Lỗi phổ biến khác:
-
Dùng “can” thay vì simple present cho facts:
- ❌ “Water can boil at 100°C.”
- ✅ “Water boils at 100°C.”
-
Nhầm “cannot” và “can not”:
- ✅ “Cannot” (một từ, thường dùng hơn)
- ✅ “Can not” (hai từ, nhấn mạnh “not”)
- ✅ “Can’t” (contraction, informal)
-
Quên negative form trong questions:
- ❌ “Why you cannot come?”
- ✅ “Why can’t you come?” / “Why can you not come?”
-
Dùng “could” khi nên dùng “was/were able to”:
- ❌ “After trying many times, I could solve it.” (ambiguous)
- ✅ “After trying many times, I was able to solve it.” (clear success)
-
Nhầm giữa can’t have (impossibility) và couldn’t have (ability):
- “She can’t have finished yet.” = Không thể nào cô ấy xong rồi (deduction – Band 9)
- “She couldn’t finish the test.” = Cô ấy không thể hoàn thành (didn’t have ability)
Bài Tập Thực Hành
Bài Tập 1: Điền Từ
Hoàn thành câu với can, cannot, could, could not (couldn’t) hoặc be able to (chia đúng dạng):
- She __ (speak) four languages fluently at present.
- When I was younger, I __ (run) 10 kilometers without getting tired.
- If we invest in education, we __ (reduce) poverty in the long term.
- Despite working hard, he __ (finish) the project on time last week. (specific success)
- Students __ (access) online libraries 24/7 nowadays.
- __ you __ (help) me with this grammar exercise?
- The government __ (ignore) climate change any longer.
- In the future, people __ (live) on Mars. (use “will be able to”)
- This problem __ (solve) easily if everyone cooperates.
- When I first arrived, I __ (understand) the local accent, but now I __ (understand) most conversations.
- Technology __ (transform) education, but it __ (replace) human teachers entirely.
- __ you __ (swim) when you were five years old?
- With proper training, employees __ (improve) their productivity significantly.
- I __ (attend) the meeting yesterday because I was sick. (couldn’t vs wasn’t able to)
- This policy __ (implemented) without public support. (passive)
Bài Tập 2: Tìm Và Sửa Lỗi
Tìm lỗi sai trong các câu sau và sửa lại:
- Students can to access information through the internet easily. [❌]
- When I was young, I could played the piano very well. [❌]
- Technology cans solve many environmental problems if used properly. [❌]
- Could you possibly to help me with this assignment? [❌]
- People cannot ignores climate change any longer. [❌]
- Last week, I could finished all my homework on time. [❌]
- She can speaks three languages fluently. [❌]
- If governments invest more, they could to reduce unemployment. [❌]
- Students can left early if they finish their exams. [❌]
- This problem could have solve earlier with proper planning. [❌]
- I have can improved my English skills recently. [❌]
- Could students to use calculators during the test? [❌]
- We cannot to deny the importance of education. [❌]
- She will can speak English fluently after this course. [❌]
- The company could has expanded into international markets. [❌]
Bài Tập 3: Viết Câu
Viết câu hoàn chỉnh sử dụng can/could, dựa trên gợi ý. Chú ý sử dụng thêm từ để câu tự nhiên và phù hợp IELTS:
Example: (technology / help / students / learn / effectively)
→ “Technology can help students learn more effectively through interactive platforms.”
-
(governments / reduce / pollution / invest / renewable energy)
→ Your answer: ___ -
(people / not / achieve / success / without / hard work)
→ Your answer: ___ -
(when / I / child / I / swim / very fast)
→ Your answer: ___ -
(online education / provide / opportunities / students / remote areas)
→ Your answer: ___ -
(if / we / act / now / we / prevent / climate change)
→ Your answer: ___ -
(she / not / attend / meeting / yesterday / because / illness) [specific past]
→ Your answer: ___ -
(artificial intelligence / replace / some jobs / future) [polite possibility]
→ Your answer: ___ -
(students / improve / language skills / practice / regularly)
→ Your answer: ___ -
(this problem / solve / cooperation / international community)
→ Your answer: ___ -
(you / explain / difference / can / could?) [polite request]
→ Your answer: ___
Bài Tập 4: IELTS Speaking Responses
Trả lời các câu hỏi sau bằng 2-3 câu, sử dụng can/could ít nhất 1 lần. Câu trả lời phải tự nhiên như trong thi thật:
Part 1:
-
Q: “Can you cook?”
A: ___ -
Q: “What languages can you speak?”
A: ___
Part 2 cue card – Nói về 1 skill bạn muốn học:
- Explain why you want to learn this skill (use “could” for future benefits):
Part 3:
-
Q: “How can governments encourage people to use public transportation?”
A: ___ -
Q: “Do you think technology can replace teachers?”
A: ___
Bài Tập 5: IELTS Writing Task 2
Viết 1 đoạn body paragraph (khoảng 100-120 từ) cho đề sau. Sử dụng can/could ít nhất 4 lần một cách tự nhiên:
Topic: “Environmental problems are becoming increasingly serious. What can individuals and governments do to address these issues?”
Requirement: Viết về solutions từ governments, sử dụng:
- “can” ít nhất 2 lần
- “could” ít nhất 2 lần
- “cannot” ít nhất 1 lần
Your paragraph:
Đáp Án Chi Tiết
Đáp Án Bài Tập 1:
-
can speak (khả năng hiện tại)
- Giải thích: “At present” chỉ hiện tại → dùng “can”
-
could run (khả năng chung trong quá khứ)
- Giải thích: “When I was younger” = khả năng general trong quá khứ
-
can reduce / could reduce (khả thi trong tương lai)
- Giải thích: Cả hai đều đúng. “Can” = chắc chắn hơn, “could” = dè dặt hơn (phù hợp IELTS hơn)
-
wasn’t able to finish / couldn’t finish (thất bại cụ thể)
- Giải thích: “Last week” + “despite” → specific situation, cả hai form đều chấp nhận được
- Lưu ý: “couldn’t finish” tự nhiên hơn trong speaking
-
can access (khả năng hiện tại)
- Giải thích: “Nowadays” = hiện tại
-
Could / help (polite request)
- Giải thích: Request lịch sự, không thêm “to”
-
cannot ignore (impossibility/necessity)
- Giải thích: “Any longer” = không thể tiếp tục → cannot
-
will be able to live (future ability)
- Giải thích: Sau “will” không dùng “can”, phải dùng “be able to”
-
can be solved (passive possibility)
- Giải thích: Passive voice với “can”
-
couldn’t understand / can understand (past vs present ability)
- Giải thích: Contrast giữa quá khứ và hiện tại
-
can transform / cannot replace (possibility vs impossibility)
- Giải thích: Balanced view – can do X but cannot do Y
-
Could / swim (past ability question)
- Giải thích: Question về quá khứ
-
can improve (general future possibility)
- Giải thích: “With proper training” = điều kiện → can
-
couldn’t attend / wasn’t able to attend (past inability)
- Giải thích: Cả hai đều đúng, “couldn’t” tự nhiên hơn
-
cannot be implemented (passive impossibility)
- Giải thích: Passive voice + necessity/impossibility
Đáp Án Bài Tập 2:
-
❌ “can to access” → ✅ “can access“
- Lỗi: Thêm “to” sau modal verb
- Quy tắc: Modal + bare infinitive (không “to”)
-
❌ “could played” → ✅ “could play“
- Lỗi: Dùng past tense sau modal
- Quy tắc: Modal + bare infinitive
-
❌ “cans solve” → ✅ “can solve“
- Lỗi: Chia modal theo ngôi thứ 3
- Quy tắc: Modal không chia theo ngôi
-
❌ “to help” → ✅ “help“
- Lỗi: Thêm “to” sau “could”
- Lưu ý: “Possibly” đúng (trạng từ), chỉ bỏ “to”
-
❌ “ignores” → ✅ “ignore“
- Lỗi: Chia động từ sau modal
- Quy tắc: Sau modal dùng V1
-
❌ “could finished” → ✅ “was able to finish / finished“
- Lỗi: Dùng “could” cho specific past success
- Quy tắc: Specific past success → “was/were able to”
-
❌ “can speaks” → ✅ “can speak“
- Lỗi: Chia động từ sau modal
- Quy tắc: Modal + V1
-
❌ “could to reduce” → ✅ “could reduce“
- Lỗi: Thêm “to”
- Quy tắc: Modal + bare infinitive
-
❌ “can left” → ✅ “can leave / are allowed to leave“
- Lỗi: Dùng past tense sau modal
- Lưu ý: Nếu nói về permission (quy định), “are allowed to” formal hơn
-
❌ “could have solve” → ✅ “could have been solved“
- Lỗi: Sai form sau “have” (phải là past participle)
- Quy tắc: Could have + past participle
- Thêm: Cần passive voice vì “problem” là object bị giải quyết
-
❌ “have can improved” → ✅ “have been able to improve“
- Lỗi: Dùng “can” trong perfect tense
- Quy tắc: Perfect tense phải dùng “have been able to”, không dùng “can”
-
❌ “Could students to use” → ✅ “Could students use“
- Lỗi: Thêm “to” trong câu hỏi
- Quy tắc: Modal + subject + bare infinitive (question form)
-
❌ “cannot to deny” → ✅ “cannot deny“
- Lỗi: Thêm “to”
- Quy tắc: Modal + bare infinitive
-
❌ “will can speak” → ✅ “will be able to speak“
- Lỗi: Dùng hai modals cạnh nhau
- Quy tắc: Không dùng modal + modal, phải dùng “will be able to”
-
❌ “could has expanded” → ✅ “could have expanded“
- Lỗi: Chia “have” thành “has”
- Quy tắc: Modal + have + past participle (have không chia)
Đáp Án Bài Tập 3:
-
Governments can reduce pollution by investing heavily in renewable energy sources.
- Alternative: “Governments could significantly reduce pollution if they invested in renewable energy.”
-
People cannot achieve success without hard work and dedication.
- Alternative: “Success cannot be achieved without persistent effort.”
-
When I was a child, I could swim very fast and often won competitions.
- Alternative: “As a child, I could swim much faster than I can now.”
-
Online education can provide learning opportunities for students in remote areas who cannot access traditional schools.
- Alternative: “Students in remote areas can benefit from online education platforms.”
-
If we act now, we can prevent the worst effects of climate change.
- Alternative: “We could potentially prevent climate catastrophe if immediate action is taken.”
-
She wasn’t able to attend the meeting yesterday because of her illness.
- Alternative: “She couldn’t attend yesterday’s meeting due to being sick.”
- Lưu ý: “Wasn’t able to” nhấn mạnh specific situation hơn
-
Artificial intelligence could potentially replace some jobs in the future, particularly in manufacturing and data processing.
- Alternative: “AI could replace routine jobs, though creative positions cannot be easily automated.”
-
Students can improve their language skills significantly if they practice regularly and consistently.
- Alternative: “With regular practice, students can achieve fluency faster than they expect.”
-
This problem can only be solved through cooperation between the international community and local governments.
- Alternative: “International cooperation could provide solutions that individual nations cannot achieve alone.”
-
Could you please explain the difference between ‘can’ and ‘could’ in polite requests?
- Alternative: “Could you help me understand when to use ‘can’ versus ‘could’?”
Đáp Án Bài Tập 4:
1. Q: “Can you cook?”
Sample A (Band 7): “Yes, I can cook quite well actually. I learned from my mother when I was a teenager, and now I can prepare most Vietnamese dishes. However, I can’t make Western food very well because I haven’t had much practice with it.”
Sample A (Band 8): “Absolutely, I can cook fairly competently. I’ve been cooking for about five years now, and I can handle most Vietnamese cuisines with confidence. That said, I cannot claim to be an expert chef – there’s still a lot I could learn, particularly about international dishes and advanced techniques.”
2. Q: “What languages can you speak?”
Sample A (Band 7): “I can speak Vietnamese fluently as it’s my mother tongue, and I can also communicate in English reasonably well. When I was younger, I could speak a little Chinese, but I can’t remember much now because I stopped practicing.”
Sample A (Band 8.5): “I can speak Vietnamese natively and English at an advanced level – I’ve been studying it for over ten years. I could also hold basic conversations in Mandarin at one point, having studied it in school, but unfortunately, I cannot claim proficiency anymore since I haven’t practiced in years. It’s one of those skills that you really cannot maintain without regular use.”
3. Skill you want to learn – future benefits:
Sample (Band 7.5): “I’m eager to learn public speaking because this skill could significantly enhance my career prospects. In my field, professionals who can present ideas convincingly often advance faster. Moreover, strong presentation skills could help me network more effectively and potentially open doors to leadership positions in the future.”
Sample (Band 8.5): “I believe mastering public speaking could be transformative for both my professional and personal development. Professionally, it could enable me to pitch ideas more persuasively and lead meetings with greater authority – skills that could accelerate my career trajectory considerably. On a personal level, it could boost my confidence in social situations and help me articulate my thoughts more clearly. I cannot overstate how valuable this skill could be in today’s communication-driven workplace.”
4. Q: “How can governments encourage people to use public transportation?”
Sample A (Band 7): “Governments can encourage this in several ways. First, they could reduce ticket prices to make public transport more affordable than driving. They can also improve the quality of buses and trains so that people can travel more comfortably. Additionally, authorities could create dedicated bus lanes so public transport can move faster during rush hours.”
Sample A (Band 8.5): “There are numerous strategies governments could implement to promote public transportation usage. Financially, they could subsidize ticket prices or introduce free travel on high-pollution days, making it more economical than private vehicles. Infrastructure-wise, authorities can invest in modernizing fleets and expanding networks so that public transport can serve more areas efficiently. They could also introduce congestion charges in city centers – a measure that has been proven to work in cities like London. Furthermore, governments can launch awareness campaigns highlighting environmental benefits, though financial incentives alone cannot drive behavior change without quality service to back them up.”
5. Q: “Do you think technology can replace teachers?”
Sample A (Band 7): “I don’t think technology can completely replace teachers. While technology can help deliver lessons and can make learning more interactive, teachers can provide emotional support and personal guidance that computers cannot offer. Students, especially young children, need human interaction that technology can’t provide.”
Sample A (Band 8.5-9): “While technology can undoubtedly enhance educational delivery, I cannot envision it completely replacing human educators. AI and online platforms can efficiently disseminate content and can adapt to individual learning paces, which is certainly beneficial. However, teachers can offer dimensions that technology simply cannot replicate – emotional intelligence, mentorship, and the ability to inspire students through personal connection. They can read subtle cues in body language, sense when someone is struggling beyond academic difficulties, and provide encouragement tailored to individual personalities. Moreover, education cannot be reduced to mere information transfer; it’s about character development and social skills, areas where human teachers remain indispensable. Therefore, while technology and teachers could work synergistically, one cannot substitute for the other entirely.”
Đáp Án Bài Tập 5:
Sample Paragraph (Band 8.0):
“Governments can take several decisive actions to address environmental degradation. Firstly, they could introduce stricter regulations that mandate companies to reduce carbon emissions and penalize non-compliance heavily. Such legislation can force industries to adopt cleaner technologies, which can significantly reduce pollution levels. Additionally, authorities could invest substantially in renewable energy infrastructure, transitioning from fossil fuels to solar and wind power. This shift cannot happen overnight; however, with sustained commitment, nations can achieve carbon neutrality within decades. Governments could also implement green tax incentives to encourage businesses to adopt eco-friendly practices. While individual efforts are valuable, systemic environmental problems cannot be solved without coordinated governmental action, as only governments possess the regulatory power and financial resources necessary to drive large-scale change.”
Phân tích:
- Can take (2 lần: “can take”, “can force”) – khả năng thực tế
- Could introduce (3 lần: “could introduce”, “could invest”, “could also”) – suggestions/proposals
- Cannot (2 lần: “cannot happen”, “cannot be solved”) – impossibility
- Sử dụng passive voice: “cannot be solved”
- Academic collocations: “take decisive actions”, “achieve carbon neutrality”
- Cohesion tốt: “Firstly”, “Additionally”, “While”
- Complex structures: relative clauses, passive, conditionals
Sample Paragraph (Band 9.0):
“To combat escalating environmental crises, governments can implement comprehensive policy frameworks that address multiple dimensions of ecological degradation simultaneously. They could legislate stringent emission standards that compel industries to transition toward sustainable practices, backed by substantial penalties that corporations cannot afford to ignore. Beyond regulation, authorities could channel significant investment into renewable energy infrastructure, recognizing that fossil fuel dependency cannot continue without catastrophic consequences. Such initiatives can yield dual benefits – environmental restoration and job creation in green sectors. Furthermore, governments could establish carbon taxation systems that internalize environmental costs, making pollution economically unviable. However, these measures cannot succeed in isolation; international cooperation remains essential, as environmental issues cannot be contained within national borders. While implementation challenges exist, the potential impact of coordinated governmental action can scarcely be overstated, given that systemic problems require systemic solutions that only state-level intervention can provide.”
Phân tích Band 9:
- Variety cao: can implement, could legislate, cannot afford, could channel, cannot continue, can yield, could establish, cannot succeed, cannot be, can scarcely be, can provide
- Sophisticated collocations: “implement comprehensive frameworks”, “compelling industries to transition”, “cannot afford to ignore”, “carbon taxation”, “can scarcely be overstated”
- Complex structures: Multiple embedded clauses, passive constructions
- Advanced vocabulary: combat, escalating, compel, catastrophic, yield, internalize, viable
- Cohesion: “Beyond regulation”, “Furthermore”, “However”, “While”
- Critical thinking: Balanced view (benefits + challenges), international dimension
Bài tập thực hành Modal Verbs Can và Could cho IELTS với đáp án chi tiết và giải thích
Đề Luyện Tập
Speaking Topics:
1. Describe a skill you have developed over time
- When và how bạn bắt đầu học skill này
- What bạn could/couldn’t do at the beginning
- What bạn can do now
- How this skill could benefit you in the future
Yêu cầu: Sử dụng “can”, “could”, “cannot” ít nhất 5 lần. Contrast giữa past ability (could/couldn’t) và present ability (can/can’t).
2. Talk about how technology has changed education
- What students couldn’t do in the past
- What students can do now thanks to technology
- What teachers still cannot be replaced by technology
- How education could evolve in the future
Yêu cầu: Sử dụng timeline rõ ràng với “could” (past), “can” (present), “could” (future). Thể hiện critical thinking về limitations.
3. Discuss environmental solutions
- What individuals can do to protect the environment
- What governments could implement
- Why some people cannot or will not change their habits
- What could happen if we don’t act
Yêu cầu: Kết hợp “can/could” với conditional sentences. Đưa ra cả solutions và consequences.
Writing Task 2 Topics:
1. Problem-Solution Essay
Topic: “In many cities, air pollution has reached dangerous levels. What are the causes of this problem, and what solutions can individuals and governments implement?”
Requirements:
- Problem paragraph: Sử dụng “can cause”, “can lead to”, “cannot be ignored”
- Solution paragraph (individuals): “can reduce”, “can adopt”, “cannot solve alone”
- Solution paragraph (governments): “could introduce”, “could invest”, “can enforce”
- Conclusion: “could potentially”, “cannot afford”
- Target: 8-10 instances của can/could tự nhiên
2. Discussion Essay
Topic: “Some people believe artificial intelligence can replace human workers in many jobs. Others think this could never happen. Discuss both views and give your opinion.”
Requirements:
- View 1: “AI can perform”, “machines can work”, “cannot make mistakes”
- View 2: “cannot replace”, “humans can provide”, “technology could never”
- Your opinion: Balance với “can… but cannot”, “could… however”
- Critical thinking: “While X can…, it cannot…”
- Target: 10-12 instances với variety cao
3. Advantage-Disadvantage Essay
Topic: “Online education is becoming more popular. What are the advantages and disadvantages of this trend?”
Requirements:
- Advantages: “Students can access”, “can learn”, “could save”, “can benefit”
- Disadvantages: “cannot interact”, “cannot develop”, “could lead to”, “can be”
- Balanced view: Mỗi advantage đi kèm một limitation
- Conclusion: “could be beneficial if…” (conditional)
- Target: 8-10 instances, combine với other structures
Writing Task 1 Practice:
1. Line graph showing trend
Scenario: Graph shows smartphone usage from 2010-2024, with projections to 2030.
Requirements:
- Overview: “It can be seen that…”, “can be observed”
- Past trends: “usage could be attributed to…”
- Current situation: “now can access”
- Future prediction: “could potentially reach”, “could increase”
- Target: 4-6 instances của can/could
2. Process diagram
Scenario: Diagram showing how solar panels generate electricity.
Requirements:
- “Solar energy can be converted…”
- “This process can generate…”
- “The system cannot function without…”
- “Excess energy can be stored…”
- Focus: Passive voice với can/could
- Target: 5-7 instances
Grammar Integration Practice:
Challenge Task: Complex Paragraph Writing
Viết 1 đoạn văn (150 từ) về topic: “The role of education in reducing poverty”
Must include:
- Can/could + relative clause: “Education, which can provide…”
- Can/could + passive: “Poverty can be reduced if…”
- Can/could + perfect infinitive: “This could have been achieved…”
- Cannot + continuous: “We cannot be ignoring…”
- Could + conditional: “If governments could invest…, they could see…”
- Collocation nâng cao: “cannot be underestimated“, “could potentially lead to“
Evaluation criteria:
- Accuracy: Tất cả can/could forms đúng ngữ pháp
- Range: Ít nhất 6 different functions của can/could
- Natural integration: Không forced, phù hợp context
- Band level: Aim for 8.0+
Self-Assessment Checklist:
Sau khi hoàn thành bài tập, check:
- ✅ Đã dùng bare infinitive (không “to”) sau can/could?
- ✅ Không chia can/could theo ngôi (không “cans”)?
- ✅ Phân biệt đúng “could” (past general) vs “was able to” (specific success)?
- ✅ Dùng can/could phù hợp với context (formal/informal)?
- ✅ Kết hợp với các structures khác (passive, relative clause)?
- ✅ Đạt target số lượng nhưng vẫn tự nhiên?
Kết Bài
Modal verbs “can” và “could” là những công cụ ngữ pháp cực kỳ linh hoạt và quan trọng trong kỳ thi IELTS. Việc sử dụng thành thạo hai modal verbs này không chỉ giúp bạn biểu đạt khả năng, khả thi, yêu cầu và gợi ý một cách chính xác, mà còn thể hiện sự tinh tế trong ngôn ngữ – một yếu tố quan trọng để đạt Band 7+.
Những điểm quan trọng cần nhớ:
Về ngữ pháp:
- Can/could luôn đi với động từ nguyên mẫu không “to”
- Không chia theo ngôi (không “cans”, “coulds”)
- Phân biệt rõ chức năng: ability, possibility, permission, request, suggestion
- Sử dụng “was/were able to” cho specific past success, không dùng “could”
Về IELTS:
- Speaking: Dùng tự nhiên, kết hợp timeline (could-past, can-present, could-future)
- Writing Task 2: Essential cho Problem-Solution essays, dùng passive voice nâng cao band score
- Writing Task 1: “Can be seen”, “could be attributed to” – academic phrases
- Combine với các structures phức (relative clauses, conditionals, passive)
Lỗi thường gặp của học viên Việt Nam:
- Thêm “to” sau modal (can to speak ❌)
- Chia modal theo ngôi (she cans ❌)
- Dùng “could” cho specific past success (Yesterday I could finish ❌)
- Không phân biệt formal/informal contexts
Để đạt Band 8+:
- Sử dụng đa dạng functions trong cùng một bài
- Kết hợp với academic collocations: “cannot be underestimated”, “could potentially lead to”
- Integrate vào complex sentences tự nhiên
- Balance giữa can (certainty) và could (tentativeness)
Hãy thực hành đều đặn với các bài tập trong bài viết này, đặc biệt chú ý đến việc sử dụng can/could trong contexts khác nhau. Ghi âm Speaking responses và tự đánh giá, viết Writing paragraphs và kiểm tra xem bạn có đạt target số lượng mà vẫn giữ được tính tự nhiên không.
Nhớ rằng, grammar chỉ là công cụ – điều quan trọng là biết khi nào, ở đâu và như thế nào để sử dụng can/could một cách hiệu quả nhất. Với sự luyện tập kiên trì và áp dụng những kiến thức trong bài viết này, bạn hoàn toàn có thể master modal verbs can/could và tự tin sử dụng chúng để đạt band điểm mục tiêu trong kỳ thi IELTS.
Chúc bạn học tốt và thành công!
