一、基础练习
1. You ___ hand it in at once, you may hand it in tomorrow.
A needn't B may not C can't D must not
2. "That must be a mistake." "No it ___ a mistake."
A must not be B needn't be C cannot be D would not be
3. You ___ go now. It's getting late.
A had rather B would C had better D would
4. Since the bus is crowded, we ___.
A had better walk to home B have better walk home
C had better walk home D had better to walk home
5. "You ___ come in now, Mary! It's getting cold!" "I ___ go on
playing in the garden."
A had better...had better B would rather...had better
C had better...would rather D had better...would have better
6. When I was a boy, I ___ chocolate.
A would like B was used to like C should like D used to like
7. I wasn't supposed to go to the movies, but I ___ myself.
A cannot help B couldn't but C had to help D couldn't help
8. Looking at my determined face, the big boy ___ pick up the fight.
A dares not B dare not C doesn't dare D dares not to
9. He began to write two hours ago. He ___ have finished the article now.
A must B ought C ought to D had to
10. You ___ to the meeting this afternoon if you have something important to
do.
A needn't to come B don't need come C don't need coming Dneedn't come
11. ___ you be here at eight o'clock tomorrow morning?
A Would B Should C Can D Could
12. ___ I have a talk with the Party Secretary now?
A Will B Did C May D Can
13. "You ___ read that article if you don't want to."
A needn't B mustn't C haven't D can't
14. When the storm comes all windows ___.
A ought to close B ought to be closing C ought to be closed D ought to closed
15. I ___ me what happened.
A would like you tell B would like you to tell
C would like you telling D would like you that you tell
16. I hope you can visit my country soon, because___ to show you some of the
beautiful places near my home.
A I like B I'd like C I will like D I shall like
17. She ___ for yesterday's test, but she didn't.
Ashould have studied B would study C might be studying Dmust have studied
18. He ___ breakfast at eight o'clock when he lived alone. But nowadays he ___
it at seven.
A was used to have ... is having B was used to having ...is having
C used to have ... has D used to having ...was
19. In the old society Grandpa Zhou ___ to work long hours a day.
A was working B was having C had D has
20. Everybody ___ in bed.
A has to spend some time B have to spend some time
C has to spend sometimes D have to spend sometimes
2) 选择合适的词或词组填空
1. I have a headache. I __________ take an aspirin.
(had better; would better)
2. He looks sleepy. He must __________ bed very late last night.
(go; have gone)
3. I want to go to the office, but you __________ with me.
(need not to go; need not go)
4. I ought __________ those books to the library last week.
(to have taken; to take)
5. The mother is telling her son, "You __________ eat with your
fingers!"
(wouldn't; mustn't)
6. He was a good swimmer so he _______ swim to the river bank when the boat
sank. (was able to; could)
7. To travel from England to Scotland you __________ a passport.
(don't need; needn't)
8. He went on foot, but he __________ by bus.
(ought have gone; should have gone)
9. A: Did Ken take the job in the bookstore?
B: No, but I think he __________.
(must have; should have)
10. He __________ talk for hours, if you let him.
(can; will)
11. You __________ use this toothbrush, it's mine.
(may not; shall not)
12. No matter what people say, I __________ do as I like.
(shall; will)
13. "I'm willing to let you take whatever you like." Means "you
______ take whatever you like." (shall; will)
14. A: I haven't felt well for a week.
B: You __________ see a doctor.
(had better; should have to)
15. A: He is late, __________ he have missed the bus?
B: Yes, he must have missed the bus.
(Can; Must)
二、强化练习
1) 选择填空
1. I didn't see her in the meeting room this morning. She _____ at the meeting.
A. mustn't have spoken B. shouldn't have spoken
C. needn't have spoken D. couldn't have spoken
2. One ought _____ for what one hasn't done.
A. not to be punished B. to not be punished
C. to not punished D. not be punished
3. If you really want yourself to be in good health, you must ___ always ___ so
much.
A. not; be smoking B. not; have smoked
C. not; to smoke D. be not; smoking
4. With so much work on hand, you _____ to see the game last night.
A. mustn't go B. shouldn't go C. couldn't have gone D. shouldn't have gone
5. Most of the students felt rather disappointed at the English party. They say
that it ______ better organized.
A. had been B. had to be C. must have been D. could have been
6. I'm surprised that he _____ in the exam.
A. should fail B. would have failed C. may have failed D. should have failed
7. The little girl _____ there alone.
A. not dare go B. dares not go C. dare not go D. dare not to go
8. "Must we do it now?" "No, you _____."
A. won't B. needn't C. can't D. don't
9. He said he would rather not _____ it right now.
A. doing B. to do C. do D. to be doing
10. You _____ to the meeting this afternoon if you have something important to
do.
A. needn't to come B. don't need come C. don't need coming D. needn't come
11. Put on more clothes. You _____ be feeling cold with only a shirt on.
A. can B. could C. would D. must
12. I _____ play football than baseball.
A. would rather B. had better C. like better D. prefer
13. I thought you _____ like something to read, so I have brought you some
books.
A. may B. might C. could D. must
14. There was plenty of times. She _____.
A. mustn't have hurried B. couldn't have hurried
C. must not hurry D. needn't have hurried
15. The plant is dead. I _____ it more water.
A. will give B. would have given C. must give D. should have given
16. You _____ return the book now. You can keep it till next week if you like.
A. can't B. mustn't C. needn't D. may not
17. It's still early, you _____.
A. mustn't hurry B. wouldn't hurry C. may not hurry D. don't have to hurry
18. Please open the window, _____?
A. can't you B. aren't you C. do you D. will you
19. We _____ for her because she never came.
A. mustn't have waited B. shouldn't have waited
C. mustn't wait D. needn't wait
20. — May I stop here? — No, you _____.
A. mustn't B. might not C. needn't D. won't
21. It's a fine day. Let's go fishing, _____.
A. won't we B. will we C. don't we D. shall we
22. I didn't see her in the meeting room this morning. She _____ at the meeting.
A. mustn't have spoken B. shouldn't have spoken
C. needn't have spoken D. couldn't have spoken
23. — Please don't make a noise.
— _____. I'll be as quiet as a mouse.
A. Yes, I won't B. No, I won't C. No, I will D. Yes, I will
24. The young man has made so much noise that he _____ not have been allowed to
attend the concert.
A. could B. must C. would D. should
25. — Where is John? — He _____ in the library.
A. should be B. must be C. can be D. must have been
26. Since the road is wet this morning, _____ last night.
A. it must rain B. it must be raining
C. it must have rained D. it must have been rain
27. — Will your brother stay home tonight?
— I'm not quite sure. He _____ to the cinema tonight.
A. must go B. can go C. may go D. may be going
28. She's already two hours late. What ______ to her?
A. can have happened B. may have happened
C. should have happened D. must happen
29. You must be a writer, _____?
A. mustn't you B. are you C. must you D. aren't you
30. I got up early that morning, but I _____ so because I had no work to do.
A. mustn't have done B. didn't need to do
C. needn't have done D. can't have done
31. He _____ have come here yesterday, but he didn't.
A. could B. should C. ought to D. all the above
32. I missed the last bus, so I _____ go home on foot.
A. must B. have to C. may D. had to
33. He ought to win the first prize, _____ he?
A. oughtn't B. shouldn't C. mustn't D. both A and B
34. Everyone _____ do his best for the modernizations of our country.
A. can B. may C. should D. might
35. Let's clean our classroom, _____?
A. will you B. don't we C. shall we D. do you
36. Let us play basketball, ______?
A. will you B. don't we C. shall we D. do you
37. He asked me for this book many times. Please tell him that he _____ have it
tomorrow.
A. must B. may C. shall D. both B and C
38. "Your phone number again? I _____ quite catch it." "It's
."
A. didn't B. couldn't C. don't D. can't
39. Mother _____ us stories when we were children.
A. was used to tell B. is used to telling C. used to tell D. used to telling
40. She would rather _____ more money on books _____ on clothes.
A. cost … not B. to spare … don't C. pay … than D. spend … than
2）强化练习题
1) You____ all those clothes! We have a washing machine to do that sort of
thing.
A) needn't have
washed B) shouldn't have washed
C) must not have
washed D) can not have washed
2) John's score on the test is the highest in the class; he____ last night.
A) should study B) should have studied
C) must have studied D) must have to study
3) The room is in a terrible mess; it ____cleaned.
A) can't have been
B) shouldn't have been
C) mustn't have been
D) wouldn't have
been
4) Nobody knows how people first came to these islands. They ____ from South
America on rafts.
A) must have sailed B) can sail C) might have sailed D) should have sailed 5) Mary was not in
her bedroom yesterday afternoon. She ____ in her classroom.
A) should have been B) must have been C) must be D) should be 6) Bob said he was
going to join our club but he didn't. He ____ his mind.
A) can't have
changed B) wouldn't have changed
C) must have changed
D) shouldn't have changed
7) You____ to town to see the film yesterday. It will be on TV tonight.
A) needn't go B) had
better not go C) should not go D) needn't have gone
8) We____ the letter yesterday, but it didn't arrive.
A) must receive B) ought to receive
C) must have received D) ought to have received
9) With all the work on hand, he____ to the cinema last night.
A) mustn't go B)
shouldn't have gone C) could not go D) couldn't have gone
10) Eve was late for class again. She ____earlier.
A) should get up B) must get up C) need to get up D) should have got
up
11) I am feeling sick. I____ so much chocolate.
A) needn't have
eaten B) couldn't have
eaten
C) mustn't have
eaten D) shouldn't have
eaten
12) I didn't send out my application form last week, but I ____.
A) had B) would do C) should have D) might have to
13) Walking alone in the deserted village, John was scared. He thought he____
Tom to go with him.
A) might have asked B) should asked C) must have asked D) should have asked
14) When I got to the cinema, the film had already started; I____ there
earlier.
A) ought to get B) ought to have got
C) must have got D) must get
15) The road was muddy. It____ last night.
A) must rained B) must have rained C) must be rained D) could have rained
16) She can speak quite fluent English. She____.
A) must been in the
U.S.A. for some time
B) must have been in
the U.S.A. for some time
C) should have been
in the U.S.A. for some time
D) May be in the
U.S.A. for some time
17) You should bear in mind that he is not so strong as he____.
A) was used to be B) used to be C) was used to D) use to
18)"We didn't see him at the exhibition yesterday.""He
___it."
A) mustn't visit B)
can't have visited C) should have gone to see D) may see
19) Mary ____my letter, otherwise she would have replied before now.
A) should have
received B) has received
C) couldn't have received D) ought to have received
20) I ____ you a valuable present for your birthday, but I was short of money.
A) would have liked
to give B) liked to give
C) have liked to
give D) would like to
give
21)"Where ____ my umbrella?""Somebody ____ it away by
mistake."
A) is, must have
taken B) is, must take
C) have been, must
take D) is, takes
22) What ____ would happen if the director knew you felt that way?
A) will you suppose B) you suppose
C) do you suppose D) you would suppose
23) Two eyes ____see more than one.
A) can B) may C) will D) should
24) ____ you continue in your efforts and achieve new and greater successes.
A) Would B) Will C) May D) Should
25) We ought to help each other in our work, ____?
A) oughtn't we B) should we C) shouldn't we D) ought to we
26) Tom ____ better than to ask Dick for help.
A) shall know B) shouldn't know C) has known D) should have known
27) You ____ your tooth pulled out before it rot completely.
A) had better got B) had to get better
C) had better to get
D) had better get
28) When we got to the cinema, the film hasn't started yet, so we ____.
A) needn't hurry B) didn't need
hurry
C) needn't to hurry D) needn't have hurried
29) It was really very dangerous; you ____ him seriously.
A) might have
injured B) could injure
C) should have
injured D) must injure
30) As he had heart attack, he was told that he ____ continue the work.
A) needn't B) may
not C) mustn't D) can't
31) An Englishman who ____not speak Italian was once traveling in Italy.
A) must B) could C) may D) might
32) I ____like to make a suggestion.
A) could B) would C)
must D) might
33) I know things are hard with you, but you ____try to get over the
difficulties.
A) can B) may C) must D) ought
34 I can't find the recorder in the room. It ____ by somebody.
A) may have been
taken away B) may leave
C) may take away D) must have taken
away
35) He ____the 9:20 train because he didn't leave home till 9:25.
A) can reach B)
could catch C) may not catch D) couldn't have caught
3) 单句改错（先判断句子是否正确，正确的句子不需改动。）
1. Ought you smoke so much?
2. If Fred didn't leave here before five, he mustn't be home yet.
3. I'm going home. I don't want to but I must, because my mother asked me not to go out after dark.
4. After I've finished my course, I'll can speak English fluently.
5. I can be seeing the top of the tower in this bedroom.
6. You are not able to play football in the park on Sundays, though you may do so on weekdays.
7. He can't be working at this hour!
8. Mary Blake ought to not be home by now.
9. His luggage is still here, he must not have left.
10. I used to writing poetry myself when I was his age.
三、能力提升
1. You _____ return the book now. You can keep it till next week if you like.
A. can't B. mustn't C. needn't D. may not
2. Where is my pen? I _____ it.
A. might lose B. would have lost C. should have lost D. must have lost
3. I wish I _____ you yesterday.
A. seen B. did see C. had seen D. were to see
4. I didn't hear the phone. I _____ asleep.
A. must be B. must have been C. should be D. should have been
5. If my lawyer _____ here last Saturday, he _____ me from going.
A. had been; would have prevented B. had been; would prevent
C. were; would prevent D. were; would have prevented
6. He _____ you more help, even though he was very busy.
A. might have given B. might have C. may have given D. may give
7. If it _____ for the snow, we _____ the mountain yesterday.
A. were not; could have climbed B. were not; could climb
C. had not been; could have climbed D. had not been; could climb
8. Without electricity human life _____ quite difficult today.
A. is B. will be C. would have been D. would be
9. A computer _____ think for itself, it must be told what to do.
A. can't B. couldn't C. may not D. might not
10. Jenny _____ have kept her word. I wonder why she changed her mind.
A. must B. should C. need D. would
11. We _____ last night, but we went to the concert instead.
A. must have studied B. might study C. should have studied D. would study
12. — Could I borrow your dictionary?
— Yes, of course you _____.
A. might B. will C. can D. should
13. Tom ought not to _____ me your secret, but he meant no harm.
A. have told B. tell C. be telling D. having told
14. — If he _____, he _____ that food.
— Luckily he was sent to the hospital immediately.
A. was warned; would not take B. had been warned; would not have taken
C. would be warned; had not taken D. would have been warned; had not taken
15. Peter _____ come with us tonight, but he isn't very sure yet.
A. must B. may C. can D. will
16. I told Sally how to get here, but perhaps I _____ for her.
A. had to write it out B. must have written it out
C. should have written it out D. ought to write it out
17. I didn't see your sister at the meeting. If she _____, she would have met
my brother.
A. has come B. did come C. came D. had come
18. — Shall I tell John about it?
— No, you _____. I've told him already.
A. needn't B. wouldn't C. mustn't D. shouldn't
19. When a pencil is partly in a glass of water, it looks as if it _____.
A. breaks B. has broken C. were broken D. had been broken
20. It's nearly seven o'clock. Jack _____ be here at any moment.
A. must B. need C. should D. can
21.— There were already five people in the car but they managed to take me as
well.
— It _____ a comfortable journey.
A. can't be B. shouldn't be C. mustn't have been D. couldn't have been
22. Johnny, you _____ play with the knife, you _____ hurt yourself.
A. won't; can't B. mustn't; may C. shouldn't; must D. can't; shouldn't
23. The fire spread through the hotel very quickly but everyone _____ get out.
A. had to B. would C. could D. was able to
24. — When can I come for the photos? I need them tomorrow afternoon.
— They _____ be ready by 12:00.
A. can B. should C. might D. need
25. — I stayed at a hotel while in New York.
— Oh, did you? You _____ with Barbara.
A. could have stayed B. could stay C. would stay D. must have stayed
26. — Will you stay for lunch?
— Sorry, _____. My brother is coming to see me.
A. I mustn't B. I can't C. I needn't D. I won't
27. — Are you coming to Jeff's party?
— I'm not sure. I _____ go to the concert instead.
A. must B. would C. should D. might
28. — Write to me when you get home.
— _____.
A. I must B. I should C. I will D. I can
29. I was really anxious about you, you _____ home without a word.
A. mustn't leave B. shouldn't have left C. couldn't have left D. needn't leave
30. — Is John coming by train?
— He should, but he _____ not. He likes driving his car.
A. must B. can C. need D. may
解答部分
基础训练部分
1—5 ACCCC 6—10 DDBCD 11—15 CCACB 16—20 BACCA
1. had better 2. have gone 3. need not go 4. to have taken
5. mustn't 6. was able to 7. don't need 8. should have gone
9. should have 10. will 11. shall not 12. will
13. shall 14. had better 15. Can
强化练习1）选择填空部分答案解析
1. D. must表示推测时不用于否定句；shouldn't have done sth. 表示"本不应该做某事而实际上做了"；needn't have done
sth. 表示"本来不必做某事而实际上做了"；couldn't have done
sth. 表示"不可能做过某事"。根据题意，选D。
2. A. 情态动词ought 后要接带to的不定式，ought to do 的否定式是ought not to do，所以答案是A。
3. A. must not always be doing sth. 表示"不要老是做谋事"，含有埋怨、指责、反感等感情色彩。
4. D. 题中的A项和B项都指现在情况；couldn't have gone表示"不可能去过"；shouldn't have gone表示"本不应该去而实际上去了"。根据题意，选D。
5. D. could have done sth. 表示"本来能够做某事而实际上未能做成"。
6. D. should可用于表示惊奇、感叹、不满等感情色彩的句子，如指过去的动作，则要用should have done sth. Would 和 may通常不带感情色彩。
7. C. 题中的dare是情态动词，后接不带to的不定式，主要用于疑问句、否定句和条件句中。
8. B. must开头的疑问句，否定答语用needn't或don't have to。
9. C. would rather通常也视为情态动词（组），后接动词原形，其否定形式为would rather not。
10. D. need作为情态动词，其否定形式为needn't；作实义动词时，其否定形式为don't (doesn't) need to do。
11. D. must用在肯定句中表推测时，语气比could, would等肯定得多。此处"must + 不定式进行式"表"想必正在……"之意。
12. A. would rather … than …，意为"宁愿（做）……而不（做）……"。
13. B. 由句意可知，这是对过去发生的事情不太有把握的推测。
14. D. needn't have done意为"过去不必做而做了某事"。
15. D. should have done表示"过去应该做而没有做某事"。
16. C. can't（不能），mustn't（不准），may not（不可以），均不合题意。
17. D. don't have to = needn't
18. D. will用在第二人称的疑问句中，为询问（或征求）对方的意愿或向对方提出请求之意。
19. B. should not have done表示"过去不应该做而做了某事"，含有"后悔"、"责备"、"劝告"，"批评"之意。
20. A. may开头的疑问句，否定答语常用mustn't。
21. D. 疑问句中shall用于第一、三人称，用来征询对方的意见。
22. D. 推测"她不可能在会上发言"，must表示推测时，不能用于否定句中。
23. B. will在此处表示"意志（向）"。
24. D. should not have done表示"过去不应该做而做了某事"，含有"后悔"、"责备"、"劝告"，"批评"之意。
25. B. must do表示对现在的事实进行推测。
26. C. must have done用于对过去发生的事情进行推测，且较有把握。
27. C. 表示推测时，must比may语气肯定。
28. A. can表推测，只用于否定句和疑问句中。
29. D. must表示推测时，其后的反意问句有两种情况：①对现存状态（现在的事实）进行推测时，反意疑问句中动词用其一般现在形式。②对过去发生的事情进行推测时，若有表过去的时间状语，反意问句用动词的过去式。
30. C. needn't have done表示"过去不必做而做了某事"，若表示"不必做某事（且实际上未做）"则用"didn't / don't
/ doesn't need to."
31. D. A表示"本能够"，B, C表"本应该"。
32. D. have to表示客观上要求做某事，must表示主观上认为必须做某事。
33. D. ought to的反意问句应用oughtn't或shouldn't开头。
34. C. should 含"按理应该做……"、"有义务做……"之意。
35. C. Let's 中的us一般包括对方在内。
36. A. Let us中的us一般不包括对方在内。
37. D. may和shall均可表"允诺"。
38. A. 由句后得知句意为"我开始没听清楚对方的电话号码"，为对过去的事实或发生动作的表述。
39. C. used to do"过去（常）做某事"，be used to
doing"习惯于做某事"。
40. D. would rather后接动词原形。Spend … on sth.为常用结构。
强化练习2）答案
1—5 ACACB 6—10 CDDDD 11—15 DCDBB 16—20 BBCCA
21—25 ACACA 26—30 DDDAC 31—35 BBCAD
强化练习3）单句改错答案
1. (No mistake)在否定句和疑问句中，ought后面的to可省。
2. mustn't — can't 3. must — have to 4. can — be able to
5. be seeing — see 6. are not able to — cannot 7. (No mistake)
8. to not — not to 9. must — can 10. writing — write
能力提升答案全解
1．C 从原题中You can keep it till
next week if you like这一信息句可知，"你不必现在还"。
2．D 从原题中Where is my pen?这一信息句可告诉考生，"笔丢了"，丢的动作是过去发生的。因此用must + have done表示对过去事实的肯定猜测。
3．C 原题中的yesterday这一信息词告诉考生，在wish后的宾语从句中，用过去完成时，表示与过去事实相反的愿望。
4．B 从原题中的I didn't hear the
phone.这一信息可以判断出，用must have done表示过去事实的准确的肯定猜测。
5．A 从原题中last Saturday这一信息词可知，条件句中用表示与过去 事实相反的过去完成时，主句用would + have done。
6．A might have + 过去分词，在次是虚拟语气，表示"本来可以给你更多的帮助"，而事实则是帮助较少。
7．C 从原题中的yesterday这一信息词暗示考生，该句应选用与过去事实相反的过去完成时，If it had not been
for … "要不是因为……"。
8．D 原题中的Without electricity相当于一个条件句：If there were no
electricity,故主句用human life would be quite difficult today.
9．A can可以表示一种客观上的能力，本句can't，表示"不能，不会"。
10．B 从原题总的"I wonder why
she changed her mind""我不知道为何他改变了主意了。"这句话告诉考生Janny没有守诺言。因此，用should + have done，表示"过去本应该做某事，而实际上没有做"。
11．C 可参看10题。意思是："昨晚本应该学习，但是却去听音乐会了。"
12．C 原题中的could不是过去时，而表示一种委婉、客气的礼貌用语。因此用could提问时，用can回答。同样用would，might提问，用will和may回答。[注意]①— Would you rather do such a thing? — Yes, I would.
②— Would you like some tea? — Yes, I would.
这两个对话中的would rather，would like是惯用法，故不能用will来回答。因为在这两个句型中，will不能去替换would。
13．A 可参看10、15题。该句意思是："汤姆本来不该告诉我你的秘密，但他没有伤害你的意思。"ought not to
have done = shouldn't have done
14．B 从答语中的Luckily he was sent
to the hospital immediately这一信息句可提示考生，条件句应填表示与过去事实相反的时态。
15．B 从原题中的but he isn't very
sure yet这一信息句可暗示考生，Peter当晚来的可能性不大。A是"准来，肯定来"，D是"将要来"。
16．C 可参看10、11、13题。"本应该"而事实上没有……
17．D 从原题中I didn't see your
sister at the meeting和后文she would have met my brother这两个信息句可知，if条件句中应填与过去事实相反的过去完成时。可参看6、7、14题。
18．A 你不必告诉他。因为I've told him
already这一信息句已暗示考生了。
19．C 当as if引导虚拟语气的句子是，如果主句与从句中的谓语词所表达的动作同时发生时，as if后接一般过去时。例如：He walked as if he
were lame.如果从句中的谓语动作发生个在主句谓语动作之前，则用过去完成时。例如：He talked as if he had known
the secret.不论主句中的谓语是现在时还是过去时。
20．C 只要考生抓住nearly一词和后文at any moment（随时的意思）这两个信息词语，就能很快选出C项，表示逻辑推测，意思是"快七点钟了，杰克一会儿就该到了。"
21．D 根据句意，是对过去情况的推测。"当时决不可能是一次舒服的乘车。"must表示对过去的推测只能用于肯定句。
22．B mustn't表示"禁止"；may表示"有可能"。句子的意思是："你不可以玩刀，可能会伤你自己。"
23．D 该题在考考生could与was able to之间的区别。Was able to表示在困难的情况下，经过一番周折而"能……"，并且成功地做了。
24．B 该题考查情态动词should表推测的用法。Can和might都可以表示可能性，用might则语气更加不肯定。Need表示"需要"、"必需"。Should可以表示推测，结合实际，合乎逻辑，意为"应当"、"该"。根据第一个说话者说的I need them tomorrow
afternoon的语境，可以确定正确答案为B。
25．A 该题在考查"情态动词+不定式的完成式"的用法，从会话的语境看，空白处应填"could + have +过去分词"表示过去本来能做到的事而事实上没有做到。
26．B 该题考查表示请求的英语口语，用will来向第二人称提问的疑问结构，是表达一种意愿和请求，是以疑问的形式来表达较为婉转的祈使语气，意思是"请你……，好吗？"，对于这种问句的肯定答语可用Sure! Certainly!
Yes, of course. I'd be glad to等；否定回答通常是I'm sorry, I can't. No, I'm
afraid I can't. I'm sorry, but … I ‘d like to, but …等。
27．D might表示"可能性"。
28．C 意思是"我会的"。对祈使句的肯定回答。
29．B shouldn't have
done为本来不该做某事，而事实上做了。
30．D 用may not可表示"可能不"。而can not则表示断然的否定推测"不可能"。A，C意思不符。
概 说
助动词(auxiliary)主要有两类：基本助动词(primary auxiliary)和情态助动词(modal auxiliary)。基本助动词有三个：do, have和be；情态助动词有十三个：may, might; can, could; will, would; shall, should; must, need,
dare, used to, ought to. 上述两类助动词的共同特征是，在协助主动词构成限定动词词组时，具有作用词的功能：
1） 构成否定式：
He didn't go and neither did she.
The meeting might not start until 5 o'clock.
2） 构成疑问式或附加疑问式：
Must you leave right now?
You have been learning French for 5 years, haven't you?
3） 构成修辞倒装：
Nowhere can he obtain any information about his sister.
Hardly had he arrived when she started complaining.
4） 代替限定动词词组：
A: Who can solve this crossword puzzle?
B: Tom can.
A: Shall I write to him?
B: Yes, do.
情态助动词的特征
基本助动词与情态助动词最主要的区别之一是，基本助动词本身没有词义，而情态助动词则有自己的词义，能表示说话人对有关动作或状态的看法，或表示主观设想：
What have you been doing since? （构成完成进行体，本身无词义）
I am afraid I must be going. （一定要）
You may have read some account of the matter. （或许已经）
除此之外，情态助动词还有如下词法和句法特征：
1） 除ought和used以外，其他情态动词后面只能接不带to的不定式。如果我们把ought to和used to看做是固定词组的话，那么，所有情态动词无一例外地只能接不带to的不定式：
We used to grow beautiful roses.
I asked if he would come and repair my television set.
2） 情态助动词在限定动词词组总总是位居第一：
They need not have been punished so severely.
3） 情态助动词用于第三人称单数现在时的时候，没有词形变化，即其词尾无-s形式：
She dare not say what she thinks.
4） 情态动词没有非限定形式，即没有不定式、-ing分词和-ed分词形式：
Still, she needn't have run away.
5） 情态助动词的“时”的形式并不是时间区别的主要标志。在不少场合，情态助动词的现在时和过去时形式都可以表示现在、过去或将来时间：
Would you mind very much if I ask you to do something?
She told him he ought not to have done it.
6） 情态助动词之间是相互排斥的，即在一个限定动词词组中只能出现一个情态助动词，但有时却可以与have和be基本助动词连用：
You should have washed the wound.
Well, you shouldn't be reading a novel.
现将情态助动词的各种形式列表如下：
情态助动词的意义和用法
情态助动词从最普通的意义上来说，是修饰分句意义的一种方式，它可以反映说话者对其表述是否真实和可能的程度作出判断。但不同的情态助动词本身所包含的意义和用法又不同，下面逐个分析。
1） can和could的用法
1. 表示能力或客观可能性，还可以表示请求和允许。如：
Can you finish this work tonight?
Man cannot live without air.
— Can I go now? — Yes, you can.
注意：①could也可表示请求，预期委婉，主要用于疑问句，不可用于肯定句，答语应用can（即could不能用于现在时态的简略答语中）。如：
Could I come to see you tomorrow?
Yes, you can. （否定答语可用No, I'm afraid not.）
②can表示能力时，还可用be able to代替。如：
I'll not be able to come this afternoon.
2. 表示惊异、怀疑、不相信的态度。（主要用在否定句、疑问句或惊叹句中）
Can this be true?
How can you be so careless!
This cannot be done by him.
3. “can(could) + have + 过去分词”的疑问或否定形式表示对过去发生的行为怀疑或不肯定。如：
He cannot have been to that town.
Can he have got the book?
2） may和might的用法
1. 表示许可。
表示请求、允许时，might比many的语气更委婉一些，否定回答时要用mustn't表示“不可以”、“禁止”、“阻止”之意。如：
You may drive the car.
— Might I use your pen? — No, you mustn't.
用May I ... 征询对方许可在文体上比较正式，在口气上比较客气。在日常口语中，用Can I ... 征询对方意见在现代口语中更为常见。
2. 用于祈使句中表示祝愿。如：
May you succeed!
3. 表示推测、可能（疑问句不能用于此意）。
He may be very busy now.
4. “may(might) + have + 过去分词”表示对过去发生的行为的推测。如：
He may not have finished the work.
3） must和have to的用法
1. 表示必须、必要。如：
You must come in time.
回答must引出的问句时，如果是否定的回答，不能用mustn't，而要用needn't或don't have to。
— Must we hand in our exercise books today?
— Yes, you must. (No, you don’t have to.)
2. “must be + 表语”的结构表示推测，它的否定或疑问式用can代替must。
This must be your pen.
3. “must + have + 过去分词”的结构常用在肯定句中，表示对过去发生的行为的推测。它的否定或疑问式用can代替must。
He must have been to Shanghai.
4. have to的含义与must相似，两者往往可以互换使用，但have to有各种形式，随have的变化而定。must与have to有下列几点不同：
① must表示的是说话人的主观看法，而have to则往往强调客观需要。如：
The play is not interesting. I really must go now.
I had to work when I was your age.
② must一般只表现在，have则有更多的时态形式。
③ 二者的否定意义不大相同。如：
You mustn't go. 你可不要去。
You don't have to go. 你不必去。
④ 询问对方的意愿时应用must。如：
Must I clean all the room?
4） dare和need的用法
1. need表示“需要”或“必须”，作情态动词时，仅用于否定句或疑问句中，在肯定句中一般用must, have to, ought to,或should代替。如：
You needn’t come so early.
— Need I finish the work today?
— Yes, you must.
注意：needn't + 不定式的完成式“表示本来不必做某事而实际上做了某事”。如：
You needn't have waited for me.
2. Dare作情态动词时，主要用于疑问句、否定句和条件从句中，一般不用在肯定句中。如：
How dare you say I'm unfair.
He daren't speak English before such a crowd, dare he?
3. Dare和need常用作实义动词，有时态、人称和数的变化，所不同的是，作实义动词时，在肯定句中，dare后面通常接带to的不定式，在否定和疑问句中，dare后面可接带to或不带to的不定式。如：
I dare to swim across this river.
He does not dare (to) answer.
Don't you dare (to) touch it!
I wondered he dare (to) say that.
He needs to finish it this evening.
5） shall和should的用法
1. Shall用于第一人称，表示征求对方的意愿。如：
What shall we do this evening?
2. Shall用于第一、第三人称疑问句中，表示说话人征求对方的意见或向对方请示。如：
Shall we begin our lesson?
When shall he be able to leave the hospital?
3. Shall用于第二、第三人称，表示说话人给对方命令、警告、允诺或威胁。如：
You shall fail if you don't work harder. （警告）
He shall have the book when I finish reading. （允诺）
He shall be punished. （威胁）
4. Should表示劝告、建议、命令，其同义词是ought to；在疑问句中，通常用should代替ought to。如：
You should go to class right away.
Should I open the window?
Should的含义较多，用法较活，现介绍三种其特殊用法。请看下面的句子：
① I should think it would be better to try it again. 我倒是认为最好再试一试。
② You are mistaken, I should say. 依我看，你是搞错了。
③ I should advise you not to do that. 我倒是劝你别这样做。
④ This is something I should have liked to ask you. 这是我本来想问你的。
从以上例句可以看出：情态动词should用于第一人称时可以表示说话人的一种谦逊、客气、委婉的语气。
Should还可以用在if引导的条件从句，表示一件事听起来可能性很小，但也不是完全没有可能。相当于“万一”的意思。从句谓语由should加动词原形构成，主句谓语却不一定用虚拟语气。如：
⑤ Ask her to ring me up if you should see her. 你万一见到她，请让她给我打个电话。
⑥ If you should change your mind, please let us know. 万一你改变主意，请通知我们。
⑦ Should I (If I should) be free tomorrow I will come. 万一我明天有时间，我就来。
此外，Why(or How) + should结构表示说话人对某事不能理解，感到意外、惊异等意思。意为“竟会”。如：
⑧ Why should you be so late today? 你几天怎么来得这么晚？
⑨ — Where is Betty living? — 贝蒂住在哪里？
— How should I know? — 我怎么会知道呢？
⑩ I don't know why you should think that I did it. 我真不知道你凭什么认为这件事是我干的。
5. “should + have + 过去分词”结构一般表示义务，表示应该做到而实际上没有做到，并包含一种埋怨、责备的口气。如：
She should have finished it.
I should have helped her, but I never could.
You should have started earlier.
6） will和would的用法
1. 表示请求、建议等，would比will委婉客气。如：
Would you pass me the book?
2. 表示意志、愿望和决心。如：
I will never do that again.
They asked if we would do that again.
3. 用“will be”和“will(would) +
have + 过去分词”的结构表示推测，主要用于第二、三人称。前者表示对目前情况的推测，后者表示对已经完成的动作或事态的推测。如：
This will be the book you want.
He will have arrived by now.
The guests would have arrived by that time.
I thought you would have finished this by now.
4. Would可表示过去反复发生的动作或某中倾向。Would表过去习惯时比used to正式，并没有“现已无此习惯”的含义。如：
The wound would not heal.
During the vacation he would visit me every week.
5. 表料想或猜想。如：
It would be about ten when he left home.
What would she be doing there?
I thought he would have told you all about it.
7） ought to的用法
1. Ought to表示应该。如：
You ought to take care of him.
2. 表示推测。注意与must表示推测时的区别：
He must be at home by now. （断定他已到家）
He ought to be home by now. （不十分肯定）
This is where the oil must be. （比较直率）
This is where the oil ought to be. （比较含蓄）
3. “ought to + have + 过去分词”表示过去应做某事而实际未做。如：
You ought to have asked him (but you didn't).
这时，ought to和should可以互相换用。
注意：在美国英语中，ought to用于否定句和疑问句时，to可以省略。如：
Ought you smoke so much?
You oughtn't smoke so much.
8） used to，had better，would rather的用法
1. Used to表示过去的习惯动作或状态，现在已不存在，在间接引语中，其形式可不变。如：
He told us he used to play football when he was young.
在疑问句、否定句、否定疑问句或强调句中，可有两种形式：
疑问句
Did you use to go to the same school as your brother?
Used you to go to the same school as your brother?
否定句
I usedn't to go there.
I didn't use to go there.
Usedn't 亦可拼作usen't，但发音皆为[ju:znt]。
否定疑问句
Usen't you to be interested in the theatre?
Didn't you use to be interested in the theatre?
强调句
I certainly used to smoke, but it was a long time ago.
I certainly did use to smoke, but it was a long time ago.
其反意疑问句或简略回答中，也有两种形式：
She used to be very fat, didn't she? （正式）/ use(d)n't
she? （口语）
Did you use to play chess? Yes, I did.
Used you to get up early in the morning? Yes, I did. (Yes, I used to.)
2. Had better意为“最好”，后接不带to的不定式。如：
— We had better go now.
— Yes, we had (we'd better / we had better).
Hadn't we better stop now? (Had we better not stop now?)
I think I'd better be going. （用于进行时态，表“最好立即”）
You had better have done that. （用于完成时态，表未完成动作）
注：①had best与had better同意，但较少用。②You had better … 用于同辈或小辈，对长辈不可用。
3. Would rather意为“宁愿”，表选择，后接不带to的不定式。如：
I'd rather not say anything.
Would you rather work on a farm?
— Wouldn't you rather stay here?
— No, I would not. I'd rather go there.
由于would rather表选择，因而后可接than。如：
I would rather work on a farm than in a factory.
I would rather watch TV than go to see the film.
I would rather lose a dozen cherry trees than that you should tell me one lie.
I'd rather you didn't talk about this to anyone. （句中的'd
rather不是情态动词，would在此是表愿望的实义动词）