Chuyên đề bồi dưỡng HSG - Chuyên đề 16: Động từ khuyết thiếu - Tiếng Anh THPT

 CHUYÊN ĐỀ 16: ĐỘNG TỪ KHUYẾT THIẾU
A. USAGES OF MODAL VERBS
1. CAN / BE ABLE TO
 CAN BE ABLE TO
"be able to" và “can" để diễn tả một khả năng hay sự có thể. Tuy nhiên, "can" không có dạng 
tương lai nên ta sử dụng "will be able to".
 Dùng để diễn tả những điều có thể làm do  Dùng để diễn tả những điều có thể làm do cố 
khả năng, năng khiếu của bản thân. gắng, xoay xở mới làm được.
 Ví dụ: I can swim. (= I have the ability to  Ví dụ: In spite of his broken leg, he was able 
swim.) to get out of the burning house.
 (Mặc dù gãy chân, anh ấy vẫn có thể thoát ra 
 khỏi ngôi nhà đang cháy.)
2. MUST / HAVE TO
 MUST HAVE TO
 Cả “must” và “have to” đều có nghĩa là “cần phải/phải”
 Diễn tả sự cần thiết phải làm gì nhưng là do  Diễn tả sự cần thiết phải làm gì nhưng là do 
chủ quan (tự bản thân nhận thức thấy) khách quan (nội quy, quy định).
 Ví dụ: I must phone my sister. ( I am  Ví dụ: Students have to go to school on time.
aware that this is necessary.) ( It’s school’s regulation.)
3. NEED
 NEED (cần)
 Need vừa là động từ thường, vừa là động từ khuyết thiếu.
 Need là động từ thường Need là động từ khuyết thiếu
 Nó phải dùng trợ động từ khi thành lập câu  Khi là động từ khuyết thiếu NEED chỉ có 
phủ định và nghi vấn. hình thức hiện tại và có đầy đủ đặc tính của 
 Động từ theo sau nó phải dùng dạng "to một động từ khuyết thiếu.
infinitive"  Ví dụ: He need work hard.
  Ví dụ: She needs to see you. You needn't go yet, need you?
 She doesn't need to see you.
4. MUSTN’T / NEEDN’T
 MUSTN’T NEEDN’T
 Mustn’t (không được phép): mang ý cấm  Needn’t (không cần thiết): mang ý nghĩa 
đoán. không bắt buộc.
 Ví dụ: You mustn’t drink it. It is poisonous.  Ví dụ: You needn’t hurry. We still have a lot 
 of time.
5. SHOULD / OUGHT TO
 SHOULD OUGHT TO
 “should” và “ought to” đều có nghĩa là “nên” dùng để đưa ra lời khuyên, ý kiến.
 Chỉ sự bắt buộc hay bổn phận nhưng ở mức  Chỉ sự bắt buộc. Mạnh hơn "Should" nhưng 
độ nhẹ hơn "Must". chưa bằng "Must".
 Ví dụ: You should send this report by 8th  Ví dụ: She really ought to apologize.
September.
6. SHALL / WILL A. should B. have to C. ought to D. must
Question 2: You______finish your homework before you go to bed.
A. must B. have to C. should D. ought to
Question 3: This drink isn't beneficial for health. You______drink it too much.
A. should B. ought to not C. ought not to D. mustn't
Question 4: This warning sign indicates that you______step on the grass.
A. shouldn't B. mustn't C. don't have to D. ought not to
Question 5: I think you______do exercise regularly in order to keep your body in good shape.
A. must B. should C. ought to D. Both B and C
Question 6: I will lend you some money, but you______pay it back to me next week.
A. should B. have to C. must D. mustn't
Question 7: Hoa______feed the cats because her mother has done it already.
A. has to B. doesn't have to C. must D. Both A and C
Question 8: Those audiences______show their tickets before entering the concert hall.
A. have to B. must C. ought to D. don't have to
Question 9: The children______spend too much time playing computer games.
A. mustn't B. ought to not C. shouldn't D. Both B and C
Question 10: In case you're suffered from the injury, you______see the doctor today.
A. had better B. must C. ought D. have better
Question 11: Water park is free for kids under 6 years old, so you______pay money for your son.
A. have to B. mustn't C. can't D. don't have to
Question 12: You look totally exhausted. You______take a rest instead of working overtime.
A. should B. ought C. must D. has better
Question 13: Anyone______have a passport, even a visa when travelling all around the world.
A. ought to B. must C. should D. has to
Question 14: In the peak season, travellers______book their accommodation in advance.
A. have to B. must C. should D. ought
Question 15: My car broke down yesterday, so I______catch a taxi to the office.
A. have to B. had better C. had to D. has to
Question 16: We______eat as much fruit as possible in order to get enough vitamins for our 
bodies.
A. had better B. should C. ought to D. All are correct
Question 17: You______tell anyone what I've revealed to you. It's still a secret.
A. mustn't B. had better not C. ought not to D. don't have to
Question 18: If you still want to maintain this relationship, you______behave improperly like that.
A. ought to not B. ought not to C. mustn't D. don't have to
Question 19: When playing or swimming in the pool, children ______ be
accompanied by their parents.
A. should B. must C. don't have to D. have to
Question 20: We______go to work by car. Sky train is a wise choice during rush hour.
A. ought to B. mustn't C. shouldn't D. have to Question 38:______it rain tomorrow, we will put off the visit to the Marble Mountains.
A. Were B. Should C. Would D. Will
Question 39: You______type these documents now. It’s not urgent.
A. can't B. needn’t C. mustn't D. may not
Question 40: Peter______come with us tonight, but I’m not sure.
A. must B. may C. can D. will
Question 41: You______touch electrical wires with wet hands.
A. needn't B. mustn't C. don't have to D. aren't allowed to
Question 42: We______last night, but we went to the concert instead.
A. must have studied B. might study
C. should have studied D. would study
Question 43: A computer______think for itself; it must be told what to do.
A. can’t B. shouldn’t C. must D. will
Question 44: Jane______have kept her word. I wonder why she changed her mind.
A. must B. should C. need D. would
Question 45: "Nancy brought some food for the party." "She______, we have plenty."
A. needn't have brought B. doesn't have to
C. didn't need to D. needn't
Question 46: I didn't hear the phone. I______asleep.
A. must be B. must have been C. should be D. should have been
Question 47: Mother______us stories when we were young.
A. was used to tell B. is used to telling C. used to tell D. used to telling
Question 48: You______return the book now. You can keep it till next week.
A. can't B. mustn't C. needn't D. may not
Question 49: What Jim says______true but I very much doubt it.
A. should be B. will be C. must be D. may be
Question 50: There was plenty of time. She______.
A. mustn't have hurriedB. couldn't have hurried
C. must not hurry D. needn't have hurried
Question 51: - "Must we do it now?" -"No, you______.”
A. won't B. needn't C. can't D. don't
Question 52: -Hurry up! Tom______for us at the school gate.
A. must wait B. must be waiting C. must be waited D. must have been waited
Question 53: - "I think Jane is at home." - "No, she______be at home, for she phoned
me from the airport just ten minutes ago."
A. mustn't B. needn't C. can't D. daren't
Question 54: There are so many types here, and I really don't know which one I
______choose.
A. should B. can C. may D. must
Question 55: I______play basketball than football.
A. would rather B. had better C. like better D. prefer Question 19: You______beat around the bush like that. I have already known the whole story.
A. should B. needn't C. shouldn't D. couldn't
Question 20: The passengers______remove the seat belts until the sign has been switched off.
A. mustn't B. can't C. needn't D. mightn't
Question 21: You . forget to meet the deadline. The boss is very strict about
being on time.
A. don't have to B. can't C. should D. mustn't
Question 22: " How old do you think Tom is?" - " He______ 17 because he is studying with my 
brother.
A. might be B. must be C. may be D. can be
Question 23: This information is very precious. You______reveal it.
A. must B. can C. needn't D. mustn't
Question 24: You______take along some cash in case of the restaurant______ accept credit cards.
A. had better - may not B. could - should not
C. has to - must not D. can - needn't
Question 25: You ______have many chances about the future job if you spoke English fluently.
A. could B. would be able to C. need D. can
Question 26: "______helping me take care of my child this morning? "
A. Can you B. Why don't you C. Would you mind D. Could you
Question 27: In the future, global warming______a level at which human life will become 
impossible.
A. will be increasing at B. increases in
C. may increase to D. will increase
Question 28: You______wear an umbrella because it isn't raining outside.
A. may B. mustn't C. should D. needn't
Question 29: Before anyone steps on that stage, you______make sure that it is secure.
A. would better B. had better C. would rather D. would prefer to
Question 30:______you looking after that cat for me while I am away?
A. Shall B. Should C. Will D. Must
Question 31:______I post that letter for you on the way to the office?
A. WouldB.WillC.Do D. Shall
Question 32: You're going to set up the equipment in a minute,______give you a hand?
A. Shall I B. Will I C. Would I D. Do I
Question 33: “Are these gloves necessary?" "Yes. You______use this chemical without gloves. It 
will bum your skin."
A. mustn’t B. don't have to C. could not D. need not
Question 34: You______so fast, or you might have an accident.
A. don't have to drive B. shouldn't have driven
C. had better not drive D. mustn't have driven
Question 35: " Did you do all the tasks yesterday?" - " No, I______it, but I spent too much time 
doing the first task."