Bare Infinitive (Động từ nguyên thể không có "to")vsTo-Infinitive (Động từ nguyên thể có "to")

Tóm tắt

Bare infinitive là động từ nguyên thể không có "to" — xuất hiện sau modal verbs (can, will, should, must...), sau let/make, và trong một số cấu trúc cố định; khác với to-infinitive ở chỗ "to" bị bỏ đi hoàn toàn.

Tại sao quan trọng

Bare infinitive là nền tảng của hầu hết câu tiếng Anh hàng ngày: - Modal verbs đều đi với bare infinitive: You should go. She can speak French. - Bỏ "to" đúng chỗ là dấu hiệu của người dùng tiếng Anh tự nhiên - Thêm "to" sai sau modal verbs là lỗi rất lộ rõ trong Writing và Speaking

Người học Việt Nam hay mắc lỗi ở đây vì hay dịch word-for-word và cảm thấy "thiếu gì đó" khi không có "to".

Cấu trúc

Bare infinitive = động từ ở dạng nguyên thể (base form), không có "to".

To-infinitive	Bare infinitive
to go	go
to study	study
to be	be
to have	have

Quy tắc đơn giản: Nếu trước động từ đã có modal verb (can, will, should, must, may, might...) — bỏ "to". Dùng bare infinitive.

Cấu trúc

Modal verb + bare infinitive (base verb — không thêm -s, -ed, -ing)

Phủ định:

Modal verb + not + bare infinitive

Câu hỏi:

Modal verb + subject + bare infinitive?

• She can speak French fluently.
• You should not ignore this problem.
• Can you help me?

Cách dùng phổ biến

1. Bare infinitive sau Modal Verbs

Tất cả modal verbs đều đi với bare infinitive, không có ngoại lệ:

can / could / will / would / shall / should / may / might / must + bare infinitive

Modal verb	Ví dụ
can	She can swim very well.
could	He could speak three languages.
will	I will help you tomorrow.
would	I would love to visit Tokyo.
shall	Shall we start?
should	You should study more regularly.
may	It may rain later today.
might	She might join us for dinner.
must	You must submit the form by Friday.

• ❌ SAI: She can to swim very well.
• ✅ ĐÚNG: She can swim very well.
• ❌ SAI: You should to study more.
• ✅ ĐÚNG: You should study more.

Cũng áp dụng với: - had better: You had better leave now. - would rather: I would rather stay at home. - used to: I used to play football every weekend. - need (khi dùng như modal): You need not worry about it. (trang trọng) - dare (khi dùng như modal): Dare he say that to her face?

2. Bare infinitive sau "let" và "make"

let + object + bare infinitive (= cho phép / để ai làm gì)
make + object + bare infinitive (= khiến ai làm gì — bắt buộc)

Let: - My parents let me stay out until midnight. - She let him borrow her car. - Let me know if you need anything. - Don't let this happen again.

Make (nghĩa cưỡng bức / gây ra): - The teacher made us repeat the exercise. - The film made me cry. - Long queues make people feel frustrated. - What made you change your mind?

Chú ý quan trọng: Khi dùng ở dạng bị động, "make" đổi sang to-infinitive: - Active: They made us work overtime. (bare infinitive) - Passive: We were made to work overtime. (to-infinitive)

3. Bare infinitive sau "help"

"Help" có thể đi với cả bare infinitive lẫn to-infinitive — cả hai đều đúng, bare infinitive tự nhiên hơn trong văn nói:

help + object + (to) bare infinitive

• Exercise helps (to) reduce stress.
• Can you help me (to) find the right answer?
• This guide will help you (to) improve your writing.

4. Bare infinitive sau "why (not)"

Dùng để gợi ý hoặc đặt câu hỏi tu từ:

Why + bare infinitive? (= tại sao lại làm vậy?)
Why not + bare infinitive? (= tại sao không...?)

• Why worry about things you can't control?
• Why not try a different approach?
• Why wait until tomorrow?
• Why not ask for help?

5. Bare infinitive trong cấu trúc cảm nhận (Perception Verbs)

Sau các động từ chỉ giác quan (see, hear, watch, feel, notice, observe) + object, dùng bare infinitive (diễn tả hành động hoàn chỉnh) hoặc -ing (diễn tả hành động đang diễn ra):

see / hear / watch / feel / notice + object + bare infinitive (hành động hoàn chỉnh)
see / hear / watch / feel / notice + object + V-ing (hành động đang xảy ra)

• I saw him cross the street. (thấy anh ta đã qua đường — hoàn chỉnh)
• I saw him crossing the street. (thấy anh ta đang qua đường)
• She heard someone knock on the door.
• We watched the sun set over the mountains.
• I felt my heart beat faster.

Dấu hiệu nhận biết

Dùng bare infinitive khi...	Ví dụ
Sau modal verbs (can/could/will/would/shall/should/may/might/must)	You should practise daily.
Sau let + object	Let me know.
Sau make + object (active voice)	She made me wait.
Sau had better / would rather	You'd better leave now.
Sau used to	I used to play tennis.
Sau why / why not	Why not try?
Sau perception verbs + object	I saw her leave.

Ví dụ

Ví dụ giao tiếp tự nhiên

• A: Should I bring anything to the party?

• B: You should bring something to drink. And let me know if you can't make it.

• A: How do I deal with stress?

• B: You could try meditation. Or why not join a yoga class? Exercise can really help clear your mind.

Ví dụ IELTS

(Speaking Part 1) "I can speak two languages — Vietnamese and English. I used to study French as well, but I haven't practised it in years. I should probably start again."

(Speaking Part 2) "This person really made me believe in myself. She would always encourage me and let me make my own decisions, which I think is the best way to learn."

(Writing Task 2) "Governments must take immediate steps to address climate change. They should invest in renewable energy and may need to introduce stricter regulations. Citizens can also contribute by making more sustainable choices."

Lỗi thường gặp

Lỗi 1: Thêm "to" sau modal verbs

• ❌ SAI: You should to study more.
• ✅ ĐÚNG: You should study more.
• ❌ SAI: She can to speak French.
• ✅ ĐÚNG: She can speak French.
• ❌ SAI: I will to help you.
• ✅ ĐÚNG: I will help you.
• TẠI SAO: Modal verbs đã là auxiliary (trợ động từ), sau chúng luôn dùng bare infinitive — không bao giờ thêm "to".

Lỗi 2: Thêm "to" sau "let" hoặc "make"

• ❌ SAI: Let me to know when you arrive.
• ✅ ĐÚNG: Let me know when you arrive.
• ❌ SAI: She made him to apologise.
• ✅ ĐÚNG: She made him apologise.
• TẠI SAO: "let + obj + bare infinitive" và "make + obj + bare infinitive" là cấu trúc cố định.

Lỗi 3: Nhầm "make" (active) và "be made" (passive)

• ❌ SAI: We were made work overtime.
• ✅ ĐÚNG: We were made to work overtime.
• TẠI SAO: Ở dạng bị động, "make" đổi thành "be made + to-infinitive".

Lỗi 4: Dùng bare infinitive sau động từ thường

• ❌ SAI: I enjoy swim every morning.
• ✅ ĐÚNG: I enjoy swimming every morning.
• ❌ SAI: She decided go by train.
• ✅ ĐÚNG: She decided to go by train.
• TẠI SAO: Bare infinitive chỉ dùng sau modal verbs và một số cấu trúc đặc biệt — không dùng sau động từ thường.

Lỗi 5: Nhầm "used to" (bare infinitive) và "be used to" (gerund)

• "I used to play tennis." → used to + bare infinitive (thói quen trong quá khứ)
• "I am used to playing tennis." → be used to + gerund (quen với việc gì)
• TẠI SAO: Hai cấu trúc này nhìn giống nhau nhưng nghĩa và cách dùng hoàn toàn khác.

So sánh với

Bare Infinitive vs. To-Infinitive

	Bare infinitive	To-infinitive
Hình thức	base verb (không có to)	to + base verb
Sau modal verbs	✅ Luôn dùng	❌ Không dùng
Sau let/make	✅ Active voice	✅ Passive voice (make)
Sau want/hope/plan	❌ Không dùng	✅ Luôn dùng
Mục đích	❌ Không dùng	✅ I study to improve.
Sau giới từ	❌ Không dùng	❌ Không dùng (dùng gerund)

Lưu ý cho người học Việt Nam

Trong tiếng Việt, "có thể đi", "nên học", "phải làm" đều dùng động từ trực tiếp sau modal. Tiếng Anh cũng tương tự — sau modal verbs dùng bare infinitive, không thêm "to":

• "Bạn nên học" → You should study (không phải "should to study")
• "Cô ấy có thể nói" → She can speak (không phải "can to speak")

Mẹo nhớ nhanh: - Nhìn thấy can/could/will/would/shall/should/may/might/must? → Bare infinitive ngay sau đó - Nhìn thấy "let someone" hoặc "make someone"? → Bare infinitive - Nhìn thấy "had better" / "would rather"? → Bare infinitive

Ứng dụng trong IELTS

IELTS Speaking — Mẫu câu hữu ích

Dùng modal verbs (rất cần thiết trong Speaking): - "I can definitely see the advantages of that approach." - "Governments should invest more in education." - "This problem might get worse if we don't act." - "You could say that technology has both positive and negative effects."

Hedging / Softening opinions (Band 7+ technique): - "It may be that social media has more drawbacks than benefits." - "There could be a number of reasons for this trend." - "This might not be the best solution."

IELTS Writing — Bare Infinitive trong câu học thuật

Đề xuất / Khuyến nghị: - "Authorities should implement stricter regulations." - "Citizens must take responsibility for their own choices."

Khả năng / Dự đoán: - "This trend may continue in the coming decades." - "The situation could worsen without immediate action."

Bài tập luyện

Điền đúng: Bare infinitive hay To-infinitive?

1. You must _____ (submit) the form before Friday.
2. She decided _____ (study) abroad.
3. Let him _____ (explain) his point of view.
4. I would rather _____ (stay) home tonight.
5. They made her _____ (redo) the entire report.
6. She was made _____ (wait) for two hours.
7. Why not _____ (try) a different method?
8. He hopes _____ (get) a promotion this year.

Sửa lỗi

1. You should to practise every day.
2. Let me to explain the situation.
3. She can to speak three languages.
4. He was made wait outside.
5. I used to playing football at school.

Đáp án

Điền đúng: 1. submit (sau must → bare infinitive) 2. to study (sau decided → to-infinitive) 3. explain (sau let + obj → bare infinitive) 4. stay (sau would rather → bare infinitive) 5. redo (sau made + obj → bare infinitive, active) 6. to wait (sau was made → passive → to-infinitive) 7. try (sau why not → bare infinitive) 8. to get (sau hopes → to-infinitive)

Sửa lỗi: 1. You should practise every day. 2. Let me explain the situation. 3. She can speak three languages. 4. He was made to wait outside. 5. I used to play football at school.

Tóm tắt nhanh

1. Bare infinitive = động từ nguyên thể không có "to"
2. Sau modal verbs (can/could/will/would/shall/should/may/might/must) → bare infinitive
3. Sau let + object và make + object (active) → bare infinitive
4. "make + object" dạng passive → to-infinitive: was made to wait
5. had better / would rather / used to → bare infinitive
6. Sau perception verbs + object (see, hear, watch...) → bare infinitive (hoàn chỉnh) hoặc -ing (đang diễn ra)
7. Đừng bao giờ viết "should to go", "can to speak" — bỏ "to" đi

Tóm tắt

To-infinitive = to + động từ nguyên thể — được dùng sau một số động từ nhất định, để diễn tả mục đích, và sau nhiều tính từ; khác với gerund (V-ing) ở chỗ nó hướng về hành động sẽ xảy ra hoặc kết quả mong muốn.

Tại sao quan trọng

To-infinitive có mặt trong hầu hết mọi câu tiếng Anh phức tạp: - Sau động từ phổ biến: want to go, hope to find, decide to stay - Diễn tả mục đích: I study English to get a better job. - Sau tính từ: It's important to practise every day.

Trong IELTS Speaking và Writing, bạn cần to-infinitive để: - Nói về mong muốn, kế hoạch, quyết định (Part 1, 2, 3) - Giải thích lý do, mục đích trong bài luận (Writing Task 2) - Tránh lỗi nhầm với gerund — một trong những lỗi thường gặp nhất ở Band 5-6

Định nghĩa

To-infinitive = to + base verb (động từ ở dạng nguyên thể)

To-infinitive	Nghĩa
to go	đi
to learn	học
to speak	nói
to finish	hoàn thành
to be	là / tồn tại
to have	có

Phân biệt "to" giới từ và "to" infinitive: - "I walk to school." → to = giới từ (chỉ hướng) - "I want to go to school." → to go = to-infinitive (sau want)

Cấu trúc

to + base verb (không thay đổi theo chủ ngữ hay thời)

Phủ định to-infinitive:

not + to + base verb

• She decided not to come to the party.
• I chose not to say anything.

To-infinitive bị động:

to + be + past participle

• The problem needs to be solved immediately.
• She wants to be promoted this year.

To-infinitive hoàn thành:

to + have + past participle

• She claims to have met him before.
• I'm lucky to have had such a great teacher.

Cách dùng phổ biến

1. To-infinitive sau động từ (Verb + to-infinitive)

Đây là cách dùng phổ biến nhất. Các động từ dưới đây bắt buộc đi với to-infinitive, không dùng gerund:

Verb + to + base verb

Động từ	Ví dụ
want	I want to travel the world.
hope	She hopes to find a new job.
plan	We plan to move next year.
decide	He decided to stay home.
need	You need to practise more.
expect	I expect to finish by noon.
promise	She promised to help me.
agree	They agreed to work together.
refuse	He refused to apologise.
offer	She offered to drive us there.
manage	I managed to fix the problem.
fail	He failed to meet the deadline.
tend	People tend to forget names.
afford	We can't afford to waste time.
appear	She appears to be very busy.
seem	It seems to be getting colder.

• ❌ SAI: I want going abroad.
• ✅ ĐÚNG: I want to go abroad.

2. To-infinitive diễn tả mục đích (Purpose)

Dùng to-infinitive thay cho "in order to" — ngắn gọn hơn, tự nhiên hơn:

[main clause] + to + base verb (= in order to + base verb)

• I study every day to improve my English.
• She went to the library to find information for her essay.
• We need to act now to protect the environment.
• Many people move to cities to find better opportunities.

Khi câu cần trang trọng hơn, dùng "in order to": - Governments must invest in education in order to reduce inequality.

Lưu ý: Không dùng "for + to-infinitive" để diễn tả mục đích khi chủ ngữ không thay đổi. - ❌ SAI: I study for to improve my English. - ✅ ĐÚNG: I study to improve my English.

3. To-infinitive sau tính từ (Adjective + to-infinitive)

It + be + adjective + to + base verb
Subject + be + adjective + to + base verb

Cấu trúc "It is + adj + to-inf": - It's important to practise speaking every day. - It's difficult to master a new language. - It was surprising to hear the news. - It is essential to consider all perspectives.

Sau tính từ mô tả cảm xúc hoặc thái độ: - I'm happy to help you. - She was surprised to see me there. - He was reluctant to admit his mistake. - I'm ready to start.

Sau tính từ mô tả thứ tự/mức độ (too/enough): - She's old enough to make her own decisions. - The problem is too complex to ignore. - He spoke too quickly to understand.

4. To-infinitive sau danh từ (Noun + to-infinitive)

Dùng to-infinitive để mô tả chức năng hoặc ý định liên quan đến danh từ:

Noun + to + base verb

• I have a lot of work to do today.
• She is looking for a place to live.
• He has the ability to learn quickly.
• This is an opportunity to improve your skills.
• Is there anything to eat in the fridge?

5. To-infinitive sau "wh-words" (Question Word + to-infinitive)

Dùng sau how, what, where, when, who, which để rút gọn mệnh đề phụ:

wh-word + to + base verb

• I don't know what to say.
• She wasn't sure where to go.
• Could you tell me how to get there?
• I've been wondering whether to apply for the job.
• We need to decide when to start.

Dấu hiệu nhận biết

Dùng to-infinitive khi...	Ví dụ
Sau: want, hope, plan, decide, need, agree, refuse, offer, manage	I want to learn.
Diễn tả mục đích (= để làm gì)	I came here to study.
Sau: It is + adj + ...	It is hard to explain.
Sau: too + adj / adj + enough	Too tired to continue
Sau: wh-word (how, what, where...)	I know how to do it.
Sau: first, last, next, only + noun	She was the first to arrive.

Ví dụ

Ví dụ giao tiếp tự nhiên

• A: Why are you studying so hard?

• B: I want to pass my IELTS exam and to apply for a scholarship abroad.

• A: What are your plans for the future?

• B: I hope to start my own business one day. I've decided to save money first so that I can afford to take that risk.

Ví dụ IELTS

(Speaking Part 1) "I tend to read in my free time. I find it difficult to concentrate if there's too much noise around me, so I prefer to read in quiet places."

(Speaking Part 2) "I'd like to talk about a goal I've been working towards. I decided to learn coding two years ago, not just to improve my career prospects, but also to challenge myself."

(Writing Task 2) "Governments need to invest in public transport to reduce traffic congestion. It is also essential to encourage citizens to consider more sustainable options. Failing to address this issue now will have long-term consequences."

Lỗi thường gặp

Lỗi 1: Dùng gerund thay to-infinitive sau want/hope/plan/decide

• ❌ SAI: I want going abroad.
• ✅ ĐÚNG: I want to go abroad.
• ❌ SAI: She hopes finding a better job.
• ✅ ĐÚNG: She hopes to find a better job.
• ❌ SAI: We plan moving to a new city.
• ✅ ĐÚNG: We plan to move to a new city.
• TẠI SAO: Trong tiếng Việt, "muốn đi", "hy vọng tìm", "dự định chuyển" đều dùng động từ trực tiếp. Trong tiếng Anh, nhóm want/hope/plan/decide chỉ đi với to-infinitive.

Lỗi 2: Bỏ "to" trong to-infinitive

• ❌ SAI: I decided stay home.
• ✅ ĐÚNG: I decided to stay home.
• ❌ SAI: She managed finish the project.
• ✅ ĐÚNG: She managed to finish the project.
• TẠI SAO: To-infinitive trong tiếng Anh bắt buộc phải có "to" (trừ trường hợp bare infinitive sau modal verbs).

Lỗi 3: Dùng to-infinitive sau giới từ (phải dùng gerund)

• ❌ SAI: I'm interested in to learn more.
• ✅ ĐÚNG: I'm interested in learning more.
• ❌ SAI: She left without to say anything.
• ✅ ĐÚNG: She left without saying anything.
• TẠI SAO: Sau giới từ (in, on, of, for, without, about...) luôn dùng gerund, không bao giờ dùng to-infinitive.

Lỗi 4: Dùng "for to" thay vì chỉ "to" cho mục đích

• ❌ SAI: I study English for to get a better job.
• ✅ ĐÚNG: I study English to get a better job.
• TẠI SAO: "For to + verb" không phải cấu trúc tiếng Anh chuẩn. Chỉ dùng "to" hoặc "in order to".

Lỗi 5: Nhầm "to" giới từ với "to" of to-infinitive

• "I'm looking forward to meeting you." → to = giới từ → sau đó dùng gerund
• "I want to meet you." → to = dấu hiệu of infinitive → sau đó dùng base verb
• TẠI SAO: "look forward to", "be used to", "in addition to" đều có "to" là giới từ → dùng gerund sau đó.

So sánh với

To-Infinitive vs. Gerund

	To-infinitive	Gerund
Hình thức	to + base verb	base verb + -ing
Hướng về	Tương lai / kết quả mong muốn	Hành động chung chung / đã xảy ra
Sau động từ	want, hope, plan, decide, need, agree...	enjoy, avoid, mind, finish, keep, suggest...
Sau giới từ	❌ Không dùng	✅ Luôn dùng
Làm chủ ngữ	To swim is fun. (ít tự nhiên)	Swimming is fun. (tự nhiên hơn)

Động từ dùng được cả hai nhưng đổi nghĩa:

Động từ	+ Gerund	+ To-infinitive
stop	He stopped smoking. (bỏ thuốc)	He stopped to smoke. (dừng lại để hút)
remember	I remember meeting her. (nhớ đã gặp)	Remember to call him. (nhớ gọi nhé)
forget	I'll never forget seeing that film. (quên lần đã xem)	Don't forget to buy milk. (đừng quên mua)
try	Try adding more spice. (thử thêm gia vị xem)	Try to sleep early. (cố gắng ngủ sớm)
regret	I regret saying that. (hối tiếc đã nói)	I regret to inform you... (tiếc phải thông báo)

Lưu ý cho người học Việt Nam

Tiếng Việt không có sự phân biệt này — "tôi muốn đi", "tôi thích đi" đều dùng động từ trực tiếp. Trong tiếng Anh: - "I want to go" (want → to-infinitive) - "I enjoy going" (enjoy → gerund)

Mẹo nhớ nhanh: 1. want, hope, plan, decide, need, agree, refuse, manage, offer, promise → to-infinitive 2. enjoy, avoid, mind, finish, keep, suggest, consider, miss, practise → gerund 3. Sau giới từ → gerund (luôn luôn) 4. Mục đích (để làm gì) → to-infinitive 5. It is + adj + ??? → to-infinitive

Ứng dụng trong IELTS

IELTS Speaking — Mẫu câu hữu ích

Nói về mục tiêu / kế hoạch: - "I'm planning to apply for a master's degree abroad." - "My goal is to become fluent in English within two years." - "I've always wanted to travel to South America."

Giải thích lý do / mục đích: - "I started exercising to improve my health." - "I moved to the city to find better career opportunities." - "People use social media to stay connected with friends."

Nói về ý kiến: - "It's important to consider both sides of the argument." - "It would be difficult to solve this problem without government support." - "I think it's essential to maintain a healthy work-life balance."

IELTS Writing — To-infinitive cho câu học thuật

Diễn tả mục đích: - "Governments must act now to prevent further environmental damage." - "Stricter laws are needed to discourage dangerous behaviour."

Diễn tả sự cần thiết: - "It is crucial to address the root causes of poverty." - "It remains important to consider the long-term consequences."

Diễn tả khả năng / xu hướng: - "Young people tend to prefer digital communication." - "This approach appears to be more effective than previous methods."

Bài tập luyện

Điền đúng dạng: To-infinitive hay Gerund?

1. I hope _____ (travel) to Europe next summer.
2. She enjoys _____ (cook) for her family.
3. He decided _____ (study) medicine.
4. They finished _____ (write) the report.
5. I go to the gym _____ (stay) healthy.
6. It's difficult _____ (learn) a new language in a short time.
7. She managed _____ (solve) the problem on her own.
8. I look forward to _____ (see) you soon.

Sửa lỗi

1. I want going to the cinema tonight.
2. She's very good at to speak English.
3. It's important practise every day.
4. I study English for to get a better job.
5. We plan moving to a larger apartment.

Đáp án

Điền đúng dạng: 1. to travel (sau hope → to-infinitive) 2. cooking (sau enjoys → gerund) 3. to study (sau decided → to-infinitive) 4. writing (sau finished → gerund) 5. to stay (mục đích → to-infinitive) 6. to learn (It's + adj + to-inf) 7. to solve (sau managed → to-infinitive) 8. seeing (look forward to → to = giới từ → gerund)

Sửa lỗi: 1. I want to go to the cinema. 2. She's very good at speaking English. 3. It's important to practise every day. 4. I study English to get a better job. 5. We plan to move to a larger apartment.

Tóm tắt nhanh

1. To-infinitive = to + động từ nguyên thể: to go, to learn, to speak
2. Sau want, hope, plan, decide, need, agree, refuse, manage, offer, promise → to-infinitive
3. Diễn tả mục đích (để làm gì): I study to improve my English
4. Sau It is + adjective: It's important to practise
5. Sau tính từ + enough / too + tính từ: old enough to decide, too hard to ignore
6. Phủ định: not to + verb → She decided not to come
7. Sau giới từ → KHÔNG dùng to-infinitive, dùng gerund thay thế