1)can 表示能力；能…会…. (过去时用could) 指本身具备的能力
Eg. We can speak English.
将来- will be able to
They will be able to tell you the news soon. 他们很快就能告诉你消息了。
过去- could 原来具备的能力.
Was/were able to do 指过去克服困难成功的做了一件事。-manage to do/succeed in doing
Eg. He could played the piano when he was 3 years old.
The fire spread through the hotel very quickly, but everyone was able to escape.
2) 推测“可能”只用于否定句或疑问句，偶尔可用于\肯定句表示“有时候可能”could 比can更不肯定 有时could不表示时态。
Eg. Can this be done by him?
This can’t be true.
The weather in Guangdong can be very cold.
3) 代替may 表许可could提出委婉的请求（注意在回答中不可用could）。
—Could I have the television on?
—Yes，you can./No，you can’t.
Can’t (choose /help) but do
Can’t help to do/doing
Eg. You can’t be too careful/ You can’t be careful enough
1)表示允许或请求/许可 might 更委婉，不用于答语。
- May/Might I use you camera?
- yes, you may/ No, you mustn’t/you may not/you’d better not
He may/might be very busy now.
He may not come tomorrow.
用心 爱心 专心 1
May God bless you!愿上帝保佑你！
May you succeed/be happy wish you happy/success
may/might as well do意为“不妨，还是……好”。
You may(just) as well tell me the truth.你还是对我说实话好。
May well do很可能做，很有理由做
You parents may well be proud of you.
1) must 表示说话人主观上的看法，即主观上的必要。have to 表示客观的需要，
My brother was very ill，so I had to call the doctor in the middle of the night.我弟弟病得很厉害，我只得半夜里把医生请来。(客观上需要做这件事)
He said that they must work hard. 他说他们必须努力工作。（主观上要做这件事）
don’t have to 表示“不必”；mustn’t表示“禁止”
You don’t have to tell him about it.你不一定要把此事告诉他。
You mustn’t tell him about it.你一定不要把这件事告诉他。
-Must I hand in my homework?
-yes, you must/No, you needn’t/don’t have to
You have worked hard all day.You must be tired.
He must be working in his office. 他一定在办公室工作呢。
must 表示对已发生的事情的推测时，must 要接完成式。 I didn’t hear the phone.I must have been asleep.
If Tom didn’t leave here until five o’clock，he can’t be home yet.
Eg. It can’t help, and he must go with me.
用心 爱心 专心 2
Why must it rain on the weekend？
Shall we begin our lesson?
2)用于二三人称的陈述句中表示发布指示、命令、允诺、答应、警告、威胁。 Eg. You shall fail if you don’t work hard.
He shall be sorry one day. I tell you. 我告诉你他早晚有一天会后悔的。
Eg. The fine shall be given in cash.
Eg. It is 8 o’clock now. He should be there at any time.
2)表惊讶或遗憾的语气。意为 “竟然会” 。常用于表感情的形容词后的that从句中。It’s strange that he should do such thing.
3) 用于条件句中表“万一”省略if, should提前。
If you should change your mind, let me know.→Should you change your mind,…..
6. will/ would
I will come tomorrow.
- I forgot to post your letter.
- I will post it myself.
Would you please pass me the book?
If you will listen, I will give you some advice.
After supper, he will sit there doing nothing.
The door won’t open.
7) would like to do
用心 爱心 专心 3
Would rather do.. than do…
Would rather sb. did/had done
这两词既可作实义动词用，又可作情态动词用。作为情态动词，两者都只能用于疑问句，否定句和条件句。 need 作实义动词时后面的不定式必须带to，而dare作实义动词用时，后面的to 时常可以被省略。
1)实义动词：need（需要，要求） need+n./to do sth.I need to have a long holiday.
dare “敢”He dares/doesn’t dare (to) go out at night.
Need you go yet?
Yes，I must./No，I needn’t./don’t have to
dare He daren’t go out alone at night.
I dare say 很可能，大概，我想
3) need，want，require，表示需要，主语指物时后面接doing/to be done
The flower needs watering/to be watered.
1) might have done sth.（表示过去，推测过去时间里可能发生的事情。）过去本来可以做但却没有做 He might have given you more help.
2) could have done sth..(对过去时间里可能发生的事情的推测) 过去本来能够做但却没有做
They could have helped us, but they were too busy.
3)ought (not) to have done sth./should (not) have done sth.本应该做某事，而事实上并没有做。否定句表示“不该做某事而做了”。
He ought not to have thrown the old clothes away.（事实上已扔了。）
4)needn’t have done sth.本没必要做某事
I dressed very warmly for the trip，but I needn’t have done so. The weather was hot.
The man must be Tom, isn’t← the man is Tom
He must have studied English for years.(he has studied ...)
用心 爱心 专心 4
You must have met him yesterday. (you met him ….)
（1）must have done “过去一定做了某事”
（2）can’t/couldn’t have done “过去不可能做了某事”
（3）may/might have done “过去可能做了某事”
（4）needn’t have done “过去本来没有必要做而做了某事”
（5）could have done “过去本来能够做某事而没有做”
（6）should/ought to have done “过去本来应该做某事而没有做”
（7）shouldn’t/oughtn’t to have done “过去本来不应该做某事而做了”
1.（2010高考英语江苏卷）---I haven’t got the reference book yet, but I’ll have a test on the subject next month.
---Don’t worry. You______ have it by Friday.
A. could B. shall C. must D. may
2.（2010高考英语上海春季卷）It is important to know about the cultural differences cause
A．must B．dare C．need D．may
3.（2010高考英语天津卷）A. needn’t B. wouldn’t C. mustn’t D. couldn’t
4.（2010高考英语四川卷）— I take the book out?
—I'm afraid not.
A. Will B. May C. Must D. Need
5.（2010高考英语陕西卷）May I take this book out of the reading room?
No, you . You read it in here.
A. mightn’t B. won’t C. needn’t D. mustn’t
6.（2010高考英语山东卷）I_______ have watched that movie —it’ll give me horrible dreams.
A. shouldn’t B. needn’t C. couldn’t D. mustn’t
7.（2010高考英语江西卷）I have told you the truth. ______ I keep repeating it?
A Must B Can C May D Will
8.（2010高考英语湖南卷）You buy a gift, but you can if you want to.
A. must B. mustn't C. have to D. don't have to
9.（2010高考英语大纲全国II卷）I’m afraid Mr.harding ____ see you now . he’s busy.
用心 爱心 专心 5
A. can’t B. mustn’t C. shouldn’t D. needn’t
10.（2010高考英语安徽卷）Jack described his father, brave boy many years ago，as a
A. would be B. would have been C. must be D. must have been
1. In case I ________ , I would try again.
A. will fail B. would miss C. should fail D. shall miss
2. Some people feel that handguns ________ .
A. should control B. should be controlled
C. must be controlling D. can be control
3. ________ open the door for you ?
A. Would you like that I B. Do you want that I
C. Will I D. Shall I
4. My son ________ the examination, but he wasn't careful enough.
A. might be able to pass B. must have passed
C. could have passed D. were able to pass
5. Isn't it strange that the lazy boy ________ pass the exam?
A. should B. has C. might D. would
6. We ________ the work so early without your help.
A. couldn't finish B. can't finish
C. couldn't have finished D. can't have finished
7. We ________ the manager, but no one ________ his telephone number.
A. could have called; knew B. could have called; had known
C. could call; had known D. could call; knew
8. -----Would you come and join them?
-----I wish I ________ . But I am busy at this moment.
A. can't B. couldn't C. could D. can
9. If Alice ________ this afternoon, the meeting should be put off.
A. would not come B. might not come C. should not come D. could not come
10. I thought you ________ like something to read, so I have brought you some books.
A. may B. might C. could D. must
11. There was plenty of time. She ________ .
A. mustn't have hurried B. couldn't have hurried
C. must not hurry D. needn't have hurried
12. It's still early, you ________ .
A. mustn't hurry B. wouldn't hurry C. may not hurry D. don't have to hurry
13. Please open the window, ________ ?
A. can't you B. aren't you C. do you D. will you
14. 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
15. He ________ you more help, even though he was very busy.
A. might have given B. might give C. may have given D. may give
16. -----Could I borrow your dictionary?
-----Yes, of course you ________ .
A. might B. will C. can D. should
用心 爱心 专心 6
17. ------ 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
18. If you really want yourself to be in good health, you must ________ always ________ so
A. not, be smoking B. not, have smoked C. not, to smoke D. be not, smoking
19. ------Where is Mary?
------ She isn't here. I think she ________ .
A. may have gone home B. must have gone home
C. might have gone home D. All the above
20. ----- I think Helen is at home.
-----No, she ________ be at home, for she phoned me from the airport just five minutes ago.
A. mustn't B. needn't C. can't D. dared not
21. She is already two hours late. What ________ to her?
A. can have happened B. may have happened
C. should have happened D. must happen
22. -----________ he be watching TV now?
------Yes, he ________ be watching TV now.
A. Must, can B. Can ,must C. Can, can D. May, must
23. You must be a writer, ________ ?
A. mustn't you B. are you C. must you D. aren't you
24. You must have seen him last night, ________ ?
A. haven't you B. didn't you C. don't you D. must you
25. I got up early this 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
26. Let's say that you could go there again, how ________ feel?
A. will you B. should you C. would you D. do you
27. A. will be B. is C. was D. should be
28. Without the leadership of the Party, there ________ no New China.
A. would be B. has been C. was D. should be
29. It is necessary that we ________ a foreign language.
A. must master B. ought to master C. master D. should master
30. Most of the students felt rather disappointed at the English party. They say that it ________
A. had been B. had to be C. must have been D. could have been
用心 爱心 专心 7