Lý thuyết Động từ Khuyết thiếu đầy đủ

Cập nhật lúc: 16:15 24-10-2016 Mục tin: Ngữ Pháp (Grammar)

Tất tần tật về nghĩa, cách dùng và ví dụ cụ thể với các động từ khuyết thiếu giúp người học nắm bắt kiến thức nhanh hơn, hiểu bài hơn và áp dụng hiệu quả hơn.








1. Could/ May/ Might + perfect: có thể là

            Dùng để chỉ một tiên đoán trong quá khứ nhưng không có cơ sở. Những động từ khiếm khuyết này đều mang nghĩa hiện tại.

Eg:      - It may have rained last night, but I am not sure.

            - The cause of death could have been bacteria.

            - John might have gone to the movies yesterday.


1.      MAY

(1)polite request

(2) formal permission

(3)more than 50% certainty


(4) exclamation as a wish

(5) after the clause with “hope”, “trust”

(6) adverb clauses of concession with “but”

(7) adverb clauses of purpose

- May I borrow your pen?

- You may leave the room.

- Where is John?

He may be at the library.


- May all your dreams come true!

- I trust (hope) that you may find this plan to your satisfaction.

- He may be poor, but he is honest. (Though he is poor...)

- She was studying so that she might read English books.


2.      MIGHT

(1)less than 50%


(2) polite request (rare)


(3) petulant reproach



(4) exclamation as a wish

(5) after the clause with “hope”, “trust”

(6) adverb clauses of concession with “but”

(7) adverb clauses of purpose

- Where is John?

He might be at the library.

- Might I borrow your pen?

- You might listen when I am talking to you. (Làm ơn ráng mà lắng nghe tôi nói)



3.      COULD




(1)Past ability

(2)polite request





(4)less than 50 % certainty


    (negative only)

- Could I borrow your pen?

- Could you help me?

-I need help in math.

You could talk to your teacher.

Where is John? He could be at home.

That couldn’t be true.

4.      CAN










(1)ability/ possibility

(2)informal permission (colloquial speech)

(3)informal polite request

(4) impossibility (negative only)

(5) = Continuous Tense when using with verbs of perception

- I can run fast.

- You can use my car tomorrow.


- Can I borrow your pen?

- That can’t be true.

Listen! I think I can hear the sound of the sea. (không dùng I am hearing)


1. Must have and can't have
Diễn đạt một ý kiến của mình theo suy luận logic.(về 1 hành động trong quá khứ)
I must have left my wallet in the car.( I am sure I did )
Jim can't have noticed you.( I am sure he didn't )

2. Must + Perfect: Dùng để nói về một tiên đoán xảy ra trong quá khứ nhưng dựa trên những cơ sở rõ ràng

Eg:      - I have lost one of my gloves. I must have dropped it somewhere.

            - My wacth says only ten past six. It must have stopped.

5.      MUST

(1)strong necessity (from speaker) -> needn’t (negative)



(3)95 % certainty-> can’t (negative)

- I must go to class today.

- Must I do it now? - No, you needn’t. Tomorrow will be soon enough.

- You must not open that door.

Mary isn’t in class. She must be sick. ( present only)

If he said that, he can’t be telling the truth.

6.      HAVE TO

(1)necessity ( from external circumstances)

(2)lack of necessity ( negative)

- I have to go to class today.

- I don’t have to go to class today.

Had to
Must không có dạng quá khứ, nên chúng ta dùng had to để thay thế.
Sorry I'm late, I had to take the children to school.
Dạng nghi vấn là Did you have to?
Did you have to work late yesterday?

7.      HAVE GOT TO


I have got to go to class today.






(1) advisability

(2) 90% certainty

- I should study tonight.

- She should do well on the test.

( future only, not present)

Should have and ought to have
Diễn đạt cảm giác của người nói khi đã nhỡ phạm phải 1 sai lầm nào đó trong quá khứ.
I should have posted this letter yesterday.( I didn't do the right thing )
You shouldn't have told me the answer.( you were wrong to do so )

9.      OUGHT TO


(2) 90 % certainty

- I ought to study tonight.

- She ought to do well on the test.

( future only, not present)


(1) polite question to make a suggestion

(2) future with “I “or “we” as subject

(3) threat


(4) determination (speaker)

(5) promise

- Shall I open the door?


- I shall arrive at 9.00

(will: more common)

- He shall suffer for this; he shall pay you what he owes you.

- These people want to buy my house, but they shan’t have it.

- If you work hard, you shall have a holiday on Saturday.


11. WILL

(1) 100% certainty


(2) willingness

(3) polite request

(4) determination (subject)




(5) promise

- He will be here at 6.00(future only)

- The phone is ringing. I’ll get it.

- Will  you please pass the salt?

- (a) George shall go out without his overcoat.

(b) George will go out without his overcoat.


Will have V(p2): diễn tả một cái gì đó sẽ được hoàn thành vào một thời gian nào đó trong tương lai.

- By 2015, I will have left my school.


(1)100% certainty

(2)definite plan

- He is going to be here at 6.00. (future only)

- I am going to paint my bedroom.

(future only)

Past plans

I was going to paint my bedroom,

but now I don’t have time.


(1) ability

(succeeded in doing)

I am able to help you.

I will be able to help you.

were/ was able to
the achievement of st difficult in the past

When I was young, I could run very fast.
Luckily, Mary was able to help us.


(1)polite request





(3)repeated action in the past = used to

- Would you please pass the salt?


- Would you mind if I left early?

I would rather go to the park than stay at home.

- Every day he would get up at six o'clock and light the fire.




 Would rather + Perfect: Ước muốn đã không xảy ra trong quá khứ

Eg:      - The film at the cinema was boring. I would rather have stayed home to watch TV.

            - He studied French at schoo; only because his parents wanted him. He would rather have studied English.

Một sự dự đoán về một sự việc mang tính chất giả thiết trong quá khứ

- Life in the Middle Ages was harsh and cruel. You would have hated it a lot.



(1)repeated action in the past

I used to talk to him via mobile phone at night.

I used to visit my grandparents every weekend.


(1)advisability with threat of

 bad result

You had better be on time, or we will leave without you.

(past form uncommon)



Class is supposed to begin at 10.

Class was supposed to begin at 10.

18. BE TO

(1)strong expectation

You are to be here at 9.00

Was/Were to have
Diễn đạt một hành động mà đáng lẽ nó đã phải xảy ra nhưng cuối cùng thì lại không xảy ra.
He was to have left yesterday.( he was supposed to leave, but he didn't )

19. NEED

(1)necessity (negative & interrogative)

You needn’t go yet, need you?



Needn't have and didn't need to
Có 1 sự khác biệt nhỏ giữa 2 cách dùng này. Hãy so sánh nhé:
I needn't have arrived at seven. - Tôi đáng nhẽ không cần phải tới lúc 7h, nhưng tôi đã làm.
( I arrived at seven, but it wasn't necessary )
I didn't need to arrive at seven. - Trước đó tôi đã biết mình không phải tới lúc 7h.
( we don't know when I arrived - maybe seven or later )
Nhưng thông thường trong văn nói, người ta thường dùng didn't need to trong cả 2 trường hợp.
In speech, have is often contracted in the forms in this unit.

20. DARE

(1)  bravery to do st

(2)  I daresay (proverb)= perhaps, it is probable

You daren’t climb that tree, dare you?

He is not here yet, but I daresay he will come later.



I. Fill in the gaps with should/shouldn’t

1.  If it´s rainy you                      take an umbrella.

2. Tom                        eat so many lollipops. It´s bad for his teeth.

3. a)                            I drink hot tea if I have a sore throat?

b) Yes, you                         .

4. They have a test tomorrow. They                     go to the cinema . They                  stay at home and study!

5. Children                    eat  lots of vegetables but they                    eat lots of sweets.

6. I have a party tonight. What                   I wear?  A dress or a pair of trousers?

7. The doctor said: "_ You                 eat healthy food. You                  eat fast food. You                  watch so much  TV. You                   walk 1 hour a day. You                  drink fruit juice and water. You                         drink wine or beer”.

8. Top of FormYou                      be so selfish. 

9. I don't think you                    smoke so much. 

10. You                 exercise more. 

11. I think you                        try to speak to her. 

12. You are overweight. You                  go on a diet. 

13. Where                           we park our car? 

14. You                        never speak to your mother like this. 

15. The kids                   spend so much time in front of the TV. 

16.                             I tell her the truth or should I say nothing? 

17. I think we                              reserve our holiday in advance. 

18. Listen to that music! Our neighbors                    play music that loud at this hour.

19. If your tooth is still hurting you tomorrow, you                    go to the dentist's.

20. Cathy                    keep ringing her ex-boyfriend. I think he is with another girl now.

21. Before going to Madrid for your holidays, you                    try and learn something of the language. You will enjoy things a lot more.

22. You                      always knock on the door before entering. This is a private office.

23. We                    bring something to Kate's party. I'll feel really embarrassed otherwise.

24. That model on the TV is too skinny. She                        eat more, I think!

25. Lizzie                   ask Bryan to help her with her studies. He did the same course last year.

26. Pregnant women                   smoke as it can damage the baby.

27. We                          leave too late tomorrow if we want to reach the beach before lunch.


II. Put in 'can', 'can't', 'could' or 'couldn't'.

1)                   you swim when you were 10?.

2) We                    get to the meeting on time yesterday, because the train was delayed by one hour.

3) He                      arrive at the party on time, even after missing the train, so he was very pleased.

4) He's amazing, he                 speak five languages, including Chinese.

5) I                   drive a car until I was 34. Then I moved to the countryside, so I had to learn.

6) I looked everywhere for my glasses but I                 find them anywhere.

7) I searched for your house for ages. luckily I                    find it in the end.

8) She's seven years old, but she                     read yet. Her parents are getting her extra lessons.

9) I read the book three times, but I                       understand it.

10) James                      speak Japanese when he lived in Japan, but he's forgotten most of it now.

11) I                         understand the chapter we had to read for homework. It was so difficult.

12) I                    lift this box - it's too heavy! Would you help me?

13) Lucy                     make it to our meeting after all. She's stuck in traffic.

14) John                    play tennis really well. He's champion of his club.

15) Unfortunately, I really                     sing at all. No-one in my family is musical either.

16) When the car broke down I was really pleased because I                    solve the problem.

17) Julian                   play excellent golf when he was only ten.

18) My grandmother                      use a computer until last month. Since then she's been taking lessons at the library.

19) I                    open this window! I think it's stuck.

20) Gill                         play the piano. She has never studied it.


1. Are you going swimming? ___ I come with you, please?

A.Should             B.Can                        C.Must                       D.Will

2. I'm not going to pay five pounds for a coffee. You ____ be joking!

A .can                   B .might                     C .must                      D .should

3. This is a hospital. People are resting, so you ______ be quiet.

A .will                  B .ought                     C .should                   D .can

4. It _____ rain, so take an umbrella.

A .might               B .must                       C .should                   D .can

5. _____ I have a quick word with you? Something important has happened.

A .Must                B .Could                     C .Would                  D .Should

6. You _______ smoke here. It's a no-smoking area.

A .couldn't           B .wouldn't               C .mightn't                D .mustn't

7. You ____ come and visit us when you are next in London.

A .could               B .might                     C .would                    D .must

8. I'm sure you _____ love this film. It's brilliant.

A .could               B .can                         C .might                     D .would

9. I _____ imagine why she married him. He's so stupid!

A .can't                 B .mightn't                 C .mustn't                   D .shouldn't

10. What _____ you do in my situation? I need your advice.

A .would              B .must                       C .could                     D .should

11. This is the most important thing - you _______ forget to take the food out of the oven at seven o'clock.

A .wouldn't          B .can't                       C .mustn't                   D .couldn't

12. They left London at three o'clock so they ______ be here by now.

A .could               B .should                   C .would

13. _________ I have more cheese on my sandwich? 

a) Must                       b) Could                     c) Would                    d) Have to 

14. You _________ eat more vegetables. 

a) should                  b) might                     c) may                                    d) could

15. I _________ like to buy the same television for my house. 

a) could                    b) must                       c) would                     d) have to

16. _________ I have a coffee please? 

a) Must                     b) Have to                  c) May                        d) Would

17. You _________ smoke near children. 

a) have to                 b) may                        c) shouldn't               d) couldn't

18. The passengers _________wear their seatbelts at all times. 

a) could                    b) must                       c) can                         d) may

19. We _________ go to the concert if the rain stops. We don't know for sure. 

a) mustn't                 b) might                     c) have to                   c) wouldn't

20. I _________ ice skate very well. 

a) can                      b) may                        c) must                       d) should

21. The boys _________wake up earlier than 7:30 am. They have class at 8:00 am. 

a) would                   b) can't                       c) could                      d) have to

22. The rock band _________play very well last year. Now they are much beter.

  a) must                      b) couldn't                 c) can                         c) should

23. You’ve been working non-stop for ten hours. You _____________ be really tired.

 A. should             B. must                 C. would rather         D. ought to

24. The fortune teller predicted that _____________ inherit a big fortune before the end of this year.

     A. will                 B. she will             C. would                   D. she would

25. I’m feeling very tired this morning. I _____________ have stayed up late last night.

      A. couldn’t         B. shouldn’t          C. mustn’t                D. to stopping

26. You’d better _____________ working so hard.
      A. stop                B. to stop               C. stopped                D. to stopping

27.  He helped her, but it was not necessary. He needn’t _____________ her.
      A. help                B. to help               C. be helping           D. have helped

28.  “_____________ you like to play a game of tennis?” “I’d love to.”
      A. Could             B. Will                   C. Do                         D. Would

29. His letter is full of mistakes. He _____________ the mistakes carefully before sending it.
      A. must have checked                     B. should have  

      C. could have checked                    D. can have checked

30.   “I bought two bottles of milk.” “You _____________ have bought milk; we have heaps of it in the house.”
      A. couldn’t         B. needn’t             C. mustn’t                D. hadn’t  

31. “I left my bike here and now it’s gone.” “Someone _____________ borrowed it.”
      A. must have      B. should have     C. couldn’t have     D. needn’t have

32. “Do you remember reading about it in the newspaper?” “No, I _____________ abroad at the time.”
      A. must have been                            B. must be               C. should be          D. should have been

33. “The door was open.” “It _____________ been open. I had looked it myself and the key was in my pocket.”
      A. mustn’t have B. must have         C. can’t have           D. shouldn’t have

34. The man was found unconscious at the foot of the cliff. He _____________ have fallen 200 meters.
      A. needn’t          B. must                  C. should                  D.mustn’t

35. “I heard their phone ringing.” “You _____________ phone ringing. They don’t have a phone.”
      A. couldn’t         B. shouldn’t          C. mustn’t                D. needn’t

36. when I’ve passed my driving test, I _____________ hire a car from our local garage.
      A. will have       B. would be able to                                C. can be able to  D. will be able to

37. When the fog lifts, we _____________ where we are.
      A. could see       B. will be able to see  C. must have seen               D. are seeing

38. You _____________ ring the bell; I have a key.
      A. may not         B. needn’t             C. mustn’t                D. couldn’t        

39. You _____________ drink this; it’s poison..

      A. must               B. needn’t             C. mustn’t                D. shouldn’t

40. Nobody knows how people first came to these islands. They _____________ have sailed from South America on drafts.
      A. might              B. must                  C. should                  D. had

41. She felt ill and _____________ leave early.
      A. has to             B. must                  C. had to                   D. ought

42. I want this letter typed, but you _____________ do it today. Tomorrow you will do.
      A. must               B. needn’t             C. couldn’t               D. mustn’t

43. “Did you hear me come in last night?” “No, I _____________ asleep.”
      A. must be          B. must have been                                  C. should be          D. should have been

44. When I first went to England, I _____________ English, but I _____________ it.
      A. can read / can’t speak                 B. can read / couldn’t 
      C. could read / couldn’t speak       D. could read / can’t speak

45. The car plunged into the river. The driver _____________ out but the passengers were drowned.
      A. is able to get B. could get           C. was able to get    D. can get

46. If you had to, _____________ you go without food and drink?    

  A. can                 B. could                 C. must                     D. will

47. I got lost and _____________ ask a policeman the way.
      A. have to           B. must have to    C .had to                   D. would

48. We _____________ reheat the pie. We can eat it cold.
      A. needn’t          B. must                  C mustn’t                 D. should have

49. we _____________ forget to shut the lift gates.
      A. should          B. must                  C. mustn’t                D. needn’t

50. The swimmer was very tired, but he _____________ the shore before he collapsed.
      A. was able to reach B. can reach  C. could reach         D. has reached

51. If a letter comes for me, _____________ you please forward it to this address>
      A. shall               B. could                 C. must                     D. should

52. The shops here don’t deliver. We _____________ carry everything home ourselves.
      A. might              B. must                  C. have to                 D. used

53. If you go to a dentist with a private practice, you _____________ pay him quite a lot of money.
      A. have to           B. must have         C. ought                    D. need

54. You _____________ talk to other candidates during the exam.
      A. shan’t             B. mustn’t             C. needn’t                D. hadn’t better

55. You had better _____________ your child so much money. It may spoil him.
      A. not give         B. not to give        C. to not give           D. don’t give

56. You can phone me, but I’d rather you _____________ it to me by email.
      A. to send           B. send                   C. sent                       D. should send   

Tất cả nội dung bài viết. Các em hãy xem thêm và tải file chi tiết dưới đây:

>> Lộ Trình Sun 2025 - 3IN1 - 1 lộ trình ôn 3 kì thi (Luyện thi TN THPT & ĐGNL; ĐGTD) tại Tuyensinh247.com. Đầy đủ theo 3 đầu sách, Thầy Cô giáo giỏi, 3 bước chi tiết: Nền tảng lớp 12; Luyện thi chuyên sâu; Luyện đề đủ dạng đáp ứng mọi kì thi.

Cập nhật thông tin mới nhất của kỳ thi tốt nghiệp THPT Quốc Gia 2021