高中英语语法-情态动词全综合讲义精品解析版（练习附答案）

情 态 动 词
一、情态动词用法
** 情态动词具有词汇意义，但意义不够完整，一般不能单独作谓语。情态动词表示说话人的语气和态度。 can; could; may; might; shall; should; will; would; must; dare; need; ought to
** 主要归纳为以下几个考查热点：
1. 情态动词基本用法；
2. 情态动词表示推测和特定的语气；
3. 情态动词 + have done 结构；
4. 情态动词和各种时态连用的含义；
n He may be a teacher.
n He may be reading in the classroom.
n He may have finished her homework.
n It must have been raining heavily when he got back, for he was wet over.
1. can的用法
①表示现在的能力 （相当于 be able to ）
Can he play the piano?
Fire can’t destroy gold.
If he doesn’t apply very soon, he won’t be able to get the job.
He ________ / ____ _____ ____ read French fluently now.
注：can的主语是人或物, be able to的主语是人，且表示具体的能够。
He is not able to swim today.他今天不能游泳。
He can't swim at all.他根本不会游泳。
e.g. She _________sing the song in English.
This machine____ make you feel comfortable.
②表示请求和允许
A: Can I go now?
B: Yes, you can. / No, you can’t.
③表示对现在的推测（只用于否定句和疑问句中，肯定句中用may/might）
【在推测可能性方面：
must(一定)＞may（可能）＞might（也许）＞can’t（不
可能）】
A: Look, someone is coming. Who ______ it be?
B: It _____ be the headmaster.
A: It _______ be him. He has gone to Beijing on business.
B: Then it _______ be Mr. Zhang. He looks like the headmaster.
④用于肯定句中表示【客观上或理论上的】可能性，“有时候可能会”（不是推测）
Children can be annoying sometimes.
Accidents can happen on such rainy days.
⑤用在否定句、疑问句、感叹句中常表惊讶、怀疑、不相信的语气。
How can you be so careless?
What can he possibly mean?
参考答案为：①can/is able to; can/be able to; can;
② can; must; can’t; may
2. could的用法
①表示过去有能力做某事。
She could play the piano when she was very young.
He could translate the article without a dictionary.
注意could和be able to的区别：
was/were able to不仅表示过去的能力与可能性,还表示“能够并确实做到”,相当于managed to do,而且重点往往在于“成功地实行”; 而could主要表示“潜在的能力”。例如:
I was able to pass the examination.我成功地通过了考试。
I could pass the examination.我曾有能力通过考试。
但在否定句中,这种“潜能”与“完成”的区别就不存在了。两者都可以表示动作的未完成。例如:
I ran after the bus, but couldn't〔wasn't able to〕 catch it.我跑着追那辆公共汽车,但没能追上。
② 表示委婉的请求(这里不是过去时态，只是用过去形式表达更委婉和客气的说法，注意回答用词)
A: Could I use your computer?
B: Certainly, you can.
另外could not have done sth过去不可能做过某事；
Could have done sth过去本能够做实际却未做。详见：11. “情态动词 + have done” 结构含义
3. may/ might的用法
may
① 表示请求或许可;
May I ask you a question?
回答可以用: Yes, you may/ Yes, please.
注意：针对一般疑问句的回答。
A: May I go there now?
B1: Yes, you may. / Yes, please
B2: No, you can't. / No, you mustn't. / No, you'd better not.表示不被许可，一般不用may not（但若按照某种规定“不可以”，也可以用）。
② 表推测（可能性小；常用于肯定句或否定句中，不用于疑问句中）
He may be a lawyer.
He may not be a lawyer.
might
① 表委婉的请求(在表示许可和请求时，用might是may的委婉形式，更礼貌，不是过去时态，因此回答时不用might形式);
A: Might I ask you a question?
B: Surely, you may. 不用might.
A: May / Might I smoke in this room?
B: Yes, you may. / No, you can’t / mustn’t.
② 表推测（可能性比may还小）
He might be a lawyer.
** may用于祈使句,表示祝愿.
May your years at Columbia be the happiest of your life, and may you blossom into just what you dream to be. 希望在哥伦比亚大学学习的四年成为你一生中最快乐的时光！祝愿你梦想成真！
May the hope and inspiration we receive from you be given back.
May you return safe and sound.
May you be happy!
4. must的用法
① “必须”(侧重说话人的主观看法) _________ 表示禁止，“千万不可以；不准”
在表“必须”这个意思之下，须要注意对于must 一般疑问句的回答
---Must we clean the classroom now?
---Yes, you________./No, you _______/________________.
②表示推测，“必定，一定”，只用于肯定的陈述句中,否定句中表示“不可能”的含义用can’t.
He must be a lawyer.他一定是个律师；
他现在不可能在家，因为昨天他去了美国。
判断：He mustn’t be at home, because he went to America yesterday. ( )
在表“必定，一定”这个意思之下，尤其需要注意must有关的反意疑问句
1）You must be joking, __________?
2）He must be a lawyer, __________?
3）He must be doing his homework upstairs now, ________?
4）He must have arrived already, __________?
5）He must have arrived yesterday, _________?
6）He must have finished the work by the end of last month, _________?
7）It must have rained last night, _________?
③ “非要，偏要，偏偏”
A: Who is the girl standing there?
B: Well, if you ______ know, her name is Mabel.
Just when I was busy, the neighbor must come and chatter.
正当我忙碌的时候，邻居偏偏过来聊天。
参考答案：①mustn’t; must; needn’t/don’t have to；②判断：错误的写法：其中mustn’t 要改为can’t；
反义疑问句：1）aren’t you;2） isn’t he; 3）isn’t he; 4）hasn’t he(若句中不含任何时间状语，即可用对应的现在完成时完成反意疑问句); 5）didn’t he(若句中含有过去的时间状语，用一般过去时完成反意疑问句); 6）hadn’t he (若句中含有过去完成时的时间状语，用过去完成时完成反意疑问句); 7）didn’t it ③must;
5. shall的用法
①用于【第一、三人称】的疑问句中表示说话人征求对方的意见或向对方请示；
Shall I help you carry that box?
_______ he wait outside or come in?
②用于【第二、三人称】的陈述句中表示说话人给对方的承诺、警告、威胁、强制、命令等语气或规定强制等意义。
If you work well, you shall have higher pay.（承诺）
If you won’t do as I tell you, you shall not go to the party.（威胁）
People under 18 shall not be employed in night work.（强制）
If you don’t get out, I shall knock you down.（警告/威胁）
③Let’s go together, ____________?
Let us go together, ______________?
参考答案：①Shall; ③ shall we; will you.
6. should的用法
①表示义务，“应该，应当”，用于各种人称
You should be polite to your teacher.
You shouldn’t spend so much time playing computer games.
②根据以往的经验或事实做出合理的推断，“照说应该, 想必，估计”
If they start today, they should arrive there in two days.
It is 12 o’clock, and I should be home in ten minutes.
I wonder where Mary is. She should be here now.
** Should用于if引导的条件状语从句中表示某件事情的可能性很小，意思是“万一”。
---What can I do for you?
---If you should see Mr. Smith, give him my regards.
③ 在某些从句中(如与“建议”、“要求”、“命令”相关的名词性从句)，表示虚拟语气．
It is suggested that we (should) make better use of the school library.
It is high time that we _______ / ___________ the problem.
④ 表惊讶、遗憾的语气 ，“竟然”
It is a pity that she should have lost all his money.
It is surprising that he should be so foolish.
注意：should+ have done有两个意思：1）本应该做实际上未做；You should finished the work yesterday; 2）表示对做过某事感到惊讶！I’m surprised that he should failed the exam.
参考答案：③solved/should solve (固定句式 It is high time that sb 过去时/should+动词原形；是某人做某事的时候了。Should不可以省略。)
7. will的用法
① 表示目前的某种倾向或习惯性动作。
He will sit there for hours, reading.
Every Saturday evening they will play chess together.
Boys will be boys.
还可以指物的固有属性,
The door____open,no matter how hard she pushed.
A.shouldn't B.couldn't C.wouldn't D.mighn't
B.couldn't过去的能力。人做主语。如果是物作主语用被动式。所以此题不选。
C. wouldn't 过去的意愿。人和物都可作主语。所以此题选它。句意是：不管她多么用力地推，这门就是不开。
②表示意志，意愿，意思是“愿意”
I have made up my mind to go and I will.
I will do my best to help you.
注意下面这句话：
If you will read the book, I´ll lend it to you. 如果你愿意读这本书，我会把它借给你。
8. would的用法
① 表示过去的习惯性动作（不表状态）　　
On Sundays he would come to see his aging parents.
He used to be a quiet boy. (　) He would be a quiet boy. ( )
② 委婉的请求
---- ___________ you do me a favor?
---- Of course, I _________.
Would you please tell me how to get to the zoo?
③表意愿（will的过去式）
I told him not to go but he wouldn’t listen to me.
④用于虚拟语气中
If he were in town, he would help you. (______________________________)
If you had come earlier, you would have seen him. (______________________________)
参考答案：① √;× ② Would; will; ④对现在的虚拟；对过去的虚拟
9. dare的用法
① 情态动词 一般用于否定句、疑问句、条件状语从句中，后接动词原形，一般现在时中，谓语动词无三单。过去式为dared。
She _______ out alone at night. 她晚上不敢一个人出去。
Not one of them ________ mention this. 他们谁也不敢提这件事。 
That was why he ______ do so. 那就是他为什么敢这样做的原因。
② 实义动词 dare to do; don’t/doesn’t/didn’t dare to do 过去式为dared。
Jack ______ the river. He looked afraid.
A. dare not to cross B. dared not cross C. dared not to cross D. doesn’t dare to cross
参考答案：①dare not go; dared; dared; ② B
10. need的用法
① 情态动词。仅用于否定句和疑问句中，肯定句中一般用
must, ought to, should代替；词形只有一个，没有将来时、
过去时或第三人称单数形式，后面接动词原形。
A: _________ I finish the work today?
B: Yes, you __________. / No, you ____________.
②实义动词。need to do； don’t/doesn’t/didn’t need to do 过去式为needed。
“need”作为实义动词时，通常用法是：
sb＋need ＋to do
sth＋need ＋doing =sth＋need ＋to be done 请看下面的例子：
1.We need to collect the parcel before we leave for England．去英国之前，我们需要收拾好行李。
2.We need to tell him the truth．我们需要告诉他真相。
3.My car needs repairing．我的汽车需要修理。
4.The flowers need watering．这些花需要浇水。
5．His leather shoes needs to be mended．他的皮鞋需要修补。
6.Her room needs cleaning．她的房间需要打扫。
参考答案：②Need；must；needn’t/don’t have to
11. “情态动词 + have done” 结构含义
①_________________过去一定做过某事
②_________________过去可能做过某事
③ ________________过去不可能做过某事
④_________________过去本应该做某事却未做
⑤_________________过去本不应该做某事却做了
⑥_________________过去本不必做某事却做了
⑦_________________过去有能力/条件做某事却未做
⑧_________________对过去行为的怀疑，表“可能做过…吗”，常用于疑问句中。
参考答案：
①must have done sth;
It must have rained last night, for the ground is wet.
② may+have+done用于肯定句中（不用于疑问句中）。
—What has happened to George?—I don't know. He may have got lost.
【若用于疑问句中可用特殊疑问词+could/can+主语+have done…?】
必修三：U2- P10-L5：What could have happened?
③can’t/couldn’t have done sth. (注:这里不用mustn’t have done)
Mr. Smith can't have gone to Beijing, for I saw him in the library just now.
④should/ought to have done sth.
Tom, you are too lazy. The work should have been finished yesterday.
I ought to have gone home last Sunday.
我理应上星期日回家.
⑤shouldn’t/ ought not to have done sth.
Look, Tom is crying. I shouldn't have been so harsh on him.
You ought not to have given him more help.
你不应该帮助他那么多.
⑥needn’t have done sth.
I needn't have bought so much wine—only five people came.
我本来没有必要买这么多酒，只来了五个人。
⑦could(不用can)+have done.
He could have passed the exam, but he was too careless.
⑧ 疑问词+can sb have done sth？
There is nowhere to find them. Where can they have gone?

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二、巩固练习
( ) 1. ----Has John arrived yet?
----No, she __________ an hour ago.
A. ought to come B. must have come
C. should come D. ought to have come
( ) 2. ---- I’m sorry, I ________ at you the other day.
---- Forget it. I was a bit out of control myself.
A. shouldn’t shout B. shouldn’t have shouted
C. mustn’t shout D. mustn’t have shouted
( ) 3. You _____ not get my support if you do such a thing.
A. shall B. must C. should D. dare
( ) 4. Hearing the steps of the police, the thief _______ move at all.
A. dares not B. dared not to C. didn’t dare to D. not dare
( ) 5. Tom, you ____ leave all your clothes on the floor like this!
A. wouldn’t B. mustn’t C. needn’t D. may not
( ) 6. ---- I hear you've got a set of valuable Australian coins. ___ I have a look?
----Yes, certainly.
A. Do B. May C. Will D. Should
( ) 7. –– She looks very happy. She _____ have passed the exam.
–– I guess so. It’s not difficult after all.
A. should B. could C. must D. might
( ) 8. It is usually warm in my hometown in March, but it ________ be rather cold sometime.
A. must B. can C. should D. would
( ) 9. My MP4 isn’t in my bag. Where _____ I have put it?
A. can B. must C. should D. would
( ) 10. John, look at the time. ________ you play the piano at such a late hour?
A. Must B. Can C. May D. Need
( ) 11. ----I've taken someone else's green sweater by mistake.
---- It __________ Harry's. He always wears green.
A. has to be B. will be
C. mustn't be D. could be
( ) 12. ---- Did you listen to the speech?
---- No, we ________ it. But we had a lot of traffic on our way..
A. must have attend B. shouldn’t have attended
C. could attend D. could have attended
( ) 13. ----________ we finish all the exercises in class?
---- Yes, you __________.
A. Shall; will B. Need; can
C. Can; might D. Must; must
( ) 14. ---- What’s the name?
---- Khulaifi. ________ I spell that for you?
A. Shall B. Would C. Can D. Might
( ) 15. Don't be worried. The news __________ be true.
A. may not B. mustn't C. needn't D. shan't
( ) 16. Some warm-blooded animals __________hibernate.
A. need not B. does not need to
C. needn't to D. do not need
( ) 17. He didn't agree with me at first but I ___________ persuade him.
A. was able to B. was able C. could D. could be able to
( ) 18. I ________ have been more than six years old when the accident happened.
A. shouldn’t B. couldn’t C. mustn’t D. needn’t
( ) 19.All the doctors in the hospital insisted that he ______ badly ill and that he ______ at once.
A. should be; should be operated on
B. should be; was operated on
C. was; should be operated on
D. was; was operated on
( ) 20.We are all for your suggestion that the discussion ______.
A. be put off B. was put off
C. should put off D. is to be put off
( ) 21.No one answers the phone call. They ______.
A. must have gone out B. can’t have gone out
C. should have gone out D. needn’t have gone out
( ) 22. ---- I don’t mind telling you what I know.
---- You ______. I’m not asking you for it.
A. mustn’t B. may not C. can’t D. needn’t
( ) 23. ---- Mum, I climbed to get the Teddy Bear from the top of the shelf.
---- My goodness! You ______ yourself. You ______ do that next time.
A. must have hurt; can’t B. should have hurt; mustn’t
C. could have hurt; mustn’t D. can’t have hurt; needn’t
( ) 24.The fire spread through the hotel very quickly but everyone ______get out.
A. would B. could C. had to D. was able to
( ) 25. ----Must we hand in our homework before we leave?
----No, you ______.
A. mustn’t B. needn’t C. have to D. can’t
( ) 26. Can you imagine that a smart man like him ______ make such a stupid mistake?
A. might B. should C. would D. need
( ) 27.When the poet was studying at Cambridge
University, he ______ take a walk along the famous river
every morning.
A. will B. could C. shall D. would
( ) 28. ---- May I smoke here?
---- If you ______, choose a seat in the smoking section.
A. should B. could C. must D. may
( ) 29. You ______ get a new bike if you do very well in the coming exam.
A. shall B. will C. should D. must
( ) 30.He did not regret saying what he did but felt that he ______ it differently.
A. could express B. would express
C. could have expressed D. must have expressed

情态动词专项练习
1.— Don’t forget to bring my new books tomorrow afternoon.
— No, I＿＿＿＿＿.
A. don’t B. can’t C. won’t D. couldn’t
2. I hear you’ve got a set of Australian coins.＿＿＿I have a look?
—— Yes, certainly.
A. Do B. May C. Shall D. Should
3. He seldom listens to others. He＿＿＿＿＿answer for what he has done.
A. shall B. will C. can D. would
4. —May I leave the office before 5 o’clock in the afternoon?
—— No, I’m afraid you＿＿＿＿.
A. needn’t B. shouldn’t C. mustn't D. won’t
5. —— Shall I tell John about it?
—— No, you＿＿. I don’t know his telephone number.
A. needn’t B. wouldn’t C. mustn’t D. shouldn’t
6. Mr Bush is on time for everything. How＿＿＿it be that he was late for the opening ceremony?
A. can B. should C. may D. must
7. The traffic light is red, so I＿＿＿stop my car.
A. must B. have to C. can D. mustn’t
8. —— What happened to the young trees we planted?
—— The trees＿＿＿well, but I didn’t water them.
A. might grow B. needn’t have grown
C. would grow D. would have grown
9. 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
10. Children＿＿＿＿＿＿＿＿in public very often.
A. should be praised
B. shouldn’t have praised
C. shouldn’t have been praised
D. shouldn’t be praised
11. Let’s clean the classroom, ＿＿＿＿＿＿＿?
A. won’t you B. shall we C. do we D. will not you
12. Tom＿＿＿＿＿＿＿show his exam results to his parents.
A. dare not B. dared C. dare to D. dares not to
13. I don’t think he＿＿＿＿＿＿＿ a new bike.
A. need to buy B. needs buy C. need D. need buy
14. — Nancy＿＿ the letter from her mother.
—No, she can’t have. The postman hasn’t come yet.
A. can receive B. can have received
C. must have received D. must receive
15. She＿＿the film. She knows nothing about it.
A. can’t see B. can’t have seen
C. must see D. mustn’t have seen
16. They must have been here the day before yesterday,＿＿＿＿?
A. mustn’t they B. didn’t they
C. mustn’t have they D. had they
17. —— I didn’t see her yesterday.
—— Oh, but you ＿＿＿＿＿＿＿＿＿＿＿.
A. must have B. ought to
C. should have D. cannot have
18. —— Must I take a bus ?
—— No, you＿＿＿＿. You can walk from here.
A. must not B. don’t
C. don’t have to D. had better not to
19. — Why do you make me do so?
— I am sorry that you＿＿＿＿＿do such a thing.
A. would B. can C. should D. may
20. — 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. won’t
21. What would have happened＿＿＿＿, as far as the river bank?
A. if Bob has walked farther
B. if Bob should walk farther
C. had Bob walked farther
D. if Bob walked farther
22. You didn’t let me drive. If we＿＿in turn, you＿＿ so tired.
A. drove; didn’t get
B. drove; wouldn’t get
C. were driving; wouldn’t get
D. had driven; wouldn’t have got
23. Without electricity human life＿＿＿＿quite different today.
A. is B. will be C. would have been D. would be
24. Oh, Janne, you’ve broken another glass. You ought ＿＿＿＿when you washed it.
A. be careful B. to care
C. have cared D. to have been careful
25. I＿__often go fishing when I lived in the countryside.
A. should B. would C. could D. might
26. He＿＿＿＿＿＿rather stay at home than go to the cinema with you.
A. should B. might C. would D. had better
27. It’s high time we＿＿＿＿＿ to the theater.
A. will B. shall C. are going to D. went
28. —— Could I use your telephone?
—— Yes, of course you ＿＿＿＿＿＿＿＿＿.
A. could B. will C. can D. might
29. It’s strange that they＿＿＿＿＿nothing about this matter.
A. know B. would know C. knows D. knew
30. I wish you＿＿＿＿＿＿go with me tomorrow.
A. will B. would C. shall D. can
31. —— Do you still remember the day when we went to the Great Wall?
—— I can’t remember it well, but＿＿＿＿＿＿sometime last autumn?
A. might it be B. could it have been
C. could it be D. must it have been
32. —— I can’t get through to the general manager’s office anyhow.
—— The line is busy. Someone＿＿the telephone.
A. must use B. uses
C. must have been using D. must be using
33. He suggests we＿＿＿＿＿＿to the cinema at once, otherwise we will be late.
A .must go B. go C. will go D. would go
34. 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
35. The general ordered that the thief＿＿＿＿.
A. be punished B. would punish
C. would be punished D. should punish
36. If only I＿＿＿＿＿how to operate a computer as you do!
A. had known B. would know
C. should know D. knew
37. It is surprising that he＿＿＿＿at the meeting.
A. was B. be C. is D. were
38. If you＿＿＿＿wait a moment, I’ll go and find our manager.
A. can B. should C. will D. must
39. —— Do you think he will do me a favor?
—— As far as I know, he is the last one to help others. He＿＿＿＿be prepared to give you a hand, though.
A. might B. must C. can D. should
40. Even though I’d hurt my leg, I＿＿＿＿＿＿ swim back to the river bank.
A. could B. might C. had to D. was able to
41. You＿＿＿＿＿＿＿go to the party if you don’t finish your homework first.
A. won’t B. don’t C. oughtn’t D. shan’t
42. —— It is rather cold here. Shall we light a fire?
—— No, we＿＿＿because things are easy to catch fire.
A. won’t B. can’t C. mustn’t D. needn’t
43. I＿＿＿＿＿＿Professor Jones had taught me this question.
A. believe B. deeply think C. wish D. suppose
44. The chairman requested that ＿＿＿＿＿＿＿.
A. the members studied the problem more carefully
B. the problems were more carefully studied
C. the problems could be studied with more care
D. the members study the problem more carefully
45. I＿＿＿＿＿＿it again.
A. would like you to read
B. would like that you read
C. would like you reading
D. would like you read
46. If you really want yourself to be in good health, you must＿＿＿always＿＿＿so much.
A. not; be smoking B. no; have smoked
C. not; to smoke D. be not; smoking
47. If I＿＿＿you, I＿＿＿＿more attention to English idioms and phrases.
A. was; shall pay B. am; will pay
C. would be; would pay D. were; would pay
48. “Would you have told him the answer had it been possible?”
“I would have, but I ＿＿＿＿so busy then.”
A. had been B. were C. was D. would be
49. He had an expression of resentment（不高兴）, as if Martin＿＿＿a fool of him.
A. had made B. makes C. made D. would make
50. ＿＿＿＿the fog, we should have reached our school.
A. Because of B. In spite of C. In case of D. But for
51. There was a half smile on his face which suggested that he＿＿＿＿happy to have given his life for his country.
A. was B. should be C. would be D. were
52. We all agreed to her suggestion that we＿＿＿＿＿＿to the Great Wall for sightseeing(观光 ).
A. will go B. go C. shall go D. should have gone
53. You must be a student, ＿＿＿＿＿＿＿＿you?
A. wasn’t B. are C. mustn’t D. aren’t
54. The young man insisted that he＿＿＿＿＿nothing wrong and＿＿＿free.
A. did； set B. had done； should be set
C. do； be set D. had done； must be set
55. Without your help, I ＿＿＿＿the exam last term.
A. failed in B. would have failed
C. wouldn’t pass D. would fail


参考答案及解析

巩固练习答案
1-5 DBACB; 6-10 BCBAA; 11-15 DDDAA; 16-20 AABCA; 21-25 ADCDB; 26-30 BDCAC

专项练习答案：
1.C。will在此表示“应诺”。
2.B。May I...?中的may用以表示“允许、许可”。
3.A。shall 用于第二、三人称的肯定句或否定句，表示说话人的意愿，有“命令、警告、威胁、强制、允诺、决心”之意。
4.C。may表示“允许”。回答may引起的问句，肯定式一般用 Yes, of course.／Yes, certainly.／Sure.／Yes, you may.否定式用No, you mustn’t.
5.A。needn’t表示“不必要”；mustn’t表示“禁止”；wouldn’t表示“拒绝”。
6.A。can表示“可能性”，通常用于否定句或疑问句中，且有时还带有“惊奇、不相信”等感情色彩。
7.B。must表示说话人的主观愿望，而have to多表示客观需要。
8.D。would have done表示对过去已发生的事情的推测，表示“可能……”。
9.B。shouldn’t have done表示“过去本来不应该做某事而事实上已经做了”。
10.D。should／should not＋do，表示“（现在）应该／不应该……”。
11.B。Let’s do sth.表示“建议做某事”，含听话一方在内，故用 shall we。如果用Let us do sth.结构，则用will you?表示请求对方允许。
12.A。情态动词dare的过去式为dared，常用于否定句、疑问句及条件句中，没有人称和数的变化，否定式是在dare后接not，再接动词原形。dare作为实义动词时，有人称和数的变化，构成否定句时，前要加助动词，后接带to或不带to的动词不定式。
13.D。need作为情态动词，一般用于否定句、疑问句及条件句中，后接动词原形。表示“现在不必干某事”,用need not do sth.；表示“过去不必干某事”，用need not have done。need作为实义动词,与其它动词用法相同，用于否定句或疑问句要加助动词。
14.C。“must have done”结构，表示对过去发生情况的肯定推测。
15.B。can’t have done，表示对过去发生情况的否定推测，意为“不可能已经……”。
16.B。must have done表示对过去发生情况的肯定推测，句中带有明确的过去时间状语，故附加疑问句用“didn’t they”。17.C。should／ought to have done表示“本来应该做的事而事实上并未做”。根据上下文，句中省去了seen her。
18.C。回答must引起的问句，否定回答用needn’t或don’t have to.
19.C。I’m sorry／surprised／disappointed之后的从句中，有时采用虚拟语气should do来表示“难过、惊奇”等情绪。
20.B。“Will you...？”在此表示邀请或请求，回答时如果用 I won’t 显得极不礼貌，也不符合下文； My brother is... me.表示“我不能来的原因”。
21.C。此题表示与过去事实相反的假设，主句用would have done,从句用had done,此处用了倒装的省略形式,即省去if, had提到句首。
22.D。参见上题。
23.D。此题表示与现在事实相反的假设，主句用should/would/might/could+do.
24。D。参见注17。
25。B。would在此表示过去的习惯、习性、倾向等，意为"常......",通常与often,sometimes,for hours等表示时间的短语连用。
26.C。would rather do sth. than do sth.为固定搭配，“宁愿做……而不愿做……”。
27.D。It’s(high／about) time that从句的谓语动词多用过去式，有时也可用should do。
28.C。Could I...？问句表示委婉的请求，若允许对方，应用can来作答，而不用could。
29.A。在It’s important／surprising／desirable／strange／necessary／no wonder／a pity／a shame＋that 从句中，从句谓语动词用（should ） do。
30.B。wish后接从句，如果从句指将来的愿望，谓语动词用would／could＋do；如果表示过去未能实现的愿望，从句谓语动词用had done；如果表示现在未能实现的愿望，从句的谓语动词用过去式，be动词用were。
31.B。could have done表示对过去发生情况的可能性推测。
32.D。must be using表示此刻“一定正在使用……”。
33.B。在suggest, demand, request，require(要求)，order(命令),insist（坚持），advise（劝告）等动词之后的宾语从句中，谓语动词要用(should) do，同时还应注意语态。
34.C。as if引导的从句，如果所说内容与事实不相符时，常用虚拟语气。此题是一种自然现象，故应用一般过去时。注意比较It seems／looks as if it is going to rain.(看起来天将要下雨。)
35.A。参见注33。
36.D。在if only引导的感叹句中，谓语动词的形式与wish后宾语从句中谓语动词的形式一样。
37.B。参见注29。
38.C。will在此为情态动词，表示“意愿”。
39.A。根据上下文可知句意为“他不愿意帮助别人，但也许他会帮你的忙”。用“might”，表示“可能性”比较小。
40.D。can表示能力时可用be able to代替。但can只有一般时和过去时，be able to可用于各种时态。如果表示“过去有能力并成功地做成了某事"时，要用was/were able to，不用could。
41.D。参见注3。
42. C。mustn’t在此表示“禁止”。
43.C。参见注 30。
44.D。参见注33。
45.A。would like sb. to do sth.意为“想要某人做某事”。为固定搭配。
46.A。mustn’t be doing与always连用，表示“一定不要总是在做……”，含有“埋怨、不满”等感情色彩。
47.D。该题表示与现在事实相反的假设，从句谓语动词用过去式，be用were，主句用would do。
48.C。该句叙述当时的真实情况，故用C。
49.A。该题中as if引导的从句表示与过去事实相反的假设，从句谓语动词用had done。
50.D。but for（要不是）引导的介词短语，相当于if it hadn’t been the fog。
51.A。该题中suggest意为“表明、暗示”，这时其后宾语从句中谓语动词用陈述语气。
52.B。在advice,demand,idea,order,plan,suggestion等名词后的同位语从句或表语从句中要用虚拟语气，其谓语形式为“（should） do”。
53.D。句中的must表示对现在的状态或现在的事实进行推测，故后面的附加疑问部分用一般现在时。
54.B。insist意为“坚持说”时，后面的宾语从句中谓语动词用陈述语气,即如果从句动作与主句动作同时发生，从句谓语用一般过去时；如果从句动作先于主句动作发生，则从句谓语用过去完成时。意为“坚决要求”时，后面宾语从句中谓语动词用“(should) do”。
55.B。本句属于隐含式虚拟语气。句中without短语相当于一个与过去事实相反的虚似条件句，故选B。


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