⑴ 表示体力或智力上的能力，即“能够，会”，可与be able to转换。
例：He can speak English. = He is able to speak English.
—Can you play basketball?
— No, I can’t.
如果表示将来具备的能力，要用will be able to。
例：If I have a good sleep, I will be able to do the problem.
例：—Can we go home now, please?
— No, you can’t.
You can only smoke in this room.
You can’t keep the library books for more than a month.
例：What can he possibly want?
例：Anybody can make mistakes.
The news can’t be true.
例：Can / Could we meet again next week? 下周我们可以再见面吗？
—What shall we do? 我们怎么办呢？
— We can / could try asking Lucy for help. ——我们可以请露茜帮忙试试看。 You can / could help me with the cooking. 你可以帮我做饭。
例：You may / can come if you wish. 如果你想来，你就来。
You may not pick flowers in this park. 本公园内不许摘花。
例：It may rain tomorrow. 明天可能会下雨。
例：Can it be true? 那会是真的吗？
例：I must go now, or I’ll be late. ten o’clock.
也就是：—Must I/we do it now？
—例：—Must I go with them?
例：She didn’t look at me. She must be angry. 她不朝我看，一定是生气了。
He is good at English. He must know the word. 他英语好，准知道这个词。
You must be Mr. Jones. 想必您就是琼斯先生吧。
4. have to的基本用法：
have to可视为情态动词，但它与其他情态动词在用法上稍有不同。其他情态动词没有人称和数的变化，而have to却有人称和数的变化，要视主语的不同而变化。 例：I / You / We / Theyto….
He / She / It
You don’t to….
Does she to…?
例：Sorry, I have to leave now. 对不起，现在我得走了。
Will hework deep into the night? 他将不得不工作到深夜吗？
⑴ need用作情态动词时，只用于否定句和疑问句。它只有一种形式，后接动词原形。 例：I don’t believe you need worry. 我相信你没有必要焦急。
—Need we go so soon? 我们需要这么早就去吗？
— Yes, we . / No, we . 是的，必须。／不，不必。
So I needn’t tell him, need I? 所以我不需要告诉他，对吧？
例如：I need to look up this word in the dictionary.
My watch needs /我的手表需要修理了。
We don’t need to work today. (= We needn’t work today.)
Does he need to go right now? (= Need he go right now?)
6. had better的基本用法：
例：You’d better get some sleep. 你最好睡一会儿。
You’d better not do that again. 你最好别再做那件事。
What had we better do now? 我们现在怎么做才好呢？
7. could, should, would, might表示推测：
如: You have worked hard all day. You must be tired. 你已辛苦工作一整天了,一定累了。 The book must be his. His name is on the cover. 这本书一定是他的,封面上写着他的名字。
【注意】 must不表推测时,在肯定句中意思为“必须(强调内在的职责)”,在否定句中意思为“不许、禁止”,以它开头的疑问句否定回答常用needn’t或don’t (doesn’t) have to。 如:We must obey the traffic rules. 我们必须遵守交通规则。
Cars mustn’t be parked here. 此处严禁停车。
—Must we hand in the papers this week? 我们必须本星期交论文吗?
—No, you needn’t. 不,你们不必(本星期交)。
②. can / could多用于否定句、疑问句或感叹句中表示推测、怀疑,两者在时间上没有差别。用can时不相信的程度更强一些
如:The man under the tree can’t be Tom. He’s gone to England. 这个人不可能是Tom,他已经去英国了。
Can it be true that he was fooled by a five-year-old boy? 他被一个五岁的孩子愚弄了,这能是真的吗?
Could this be an excuse? 这会不会是个借口?
How can you be so careless! 你怎么这样粗心!
③.may / might多用来表示把握性不大的推测,意思为“也许、可能”, might比may的把握性更小一些。
用法区别 常用位置 may be may为情态动词，be为动词原形 句中，作谓语
maybe 副词，大概、也许，相当于perhaps 句首，作状语
如:Mr. Wang may know Professor Li’s telephone number.王先生也许知道李教授的电话号码。
This 这可能就是汤姆一直在找的钥匙。 She be there today. 今天她可能不在那儿。
一、 典型例题 【中考链接】
（ ）1．—Who is the man over there? Is it Mr. Li?
— No, it ______ be him. Mr. Li is much taller.
A. mustn’t B. may no C. can’t D. needn’t
（ ）2．—Must I go with them tomorrow？
A. mustn't B. shouldn't C. needn't D. can't
（ ）3．—______ I take some photos in the hall?
— No, you ______.
A. Can, needn’t B. Must, mustn’t C. Could, won’t D. May, mustn’t
（ ）4．—Dad, must I finish my homework today?
—No, you ________. You may do it tomorrow.
A. needn’t B. mustn’t C. don’t D. won’t
（ ）5．—The lake is said to be dry. Is that true?
—It _______.Look, some kids are swimming in it.
A. must be true B. can’t be true C. may not be true
（ ）6．—What is your mother going to do this Saturday?
—I’m not sure. She _____ go to see my grandmother.
A. can B. must C. may
（ ）7．—Susan has bought a large house with a swimming pool.
—It ______ be very expensive. I never even dream about it.
A. must B. might C. can’t D. shouldn’t
（ ）8．—Listen! Is Professor Johnson giving a report in the hall?
—No, it be him. He has gone to Japan.
A. needn’t B. may not C. mustn’t D. can’t
（ ）9．—Let’s go to the West Hill Park by taxi.
—Oh, it is not far away from here. We _______take a taxi.
A. couldn’t B. mustn’t C. needn’t D. can’t
（ ）10．—Can you play the piano?
—Yes, I _______. I often practice it on weekends.
A. needn’t B. need C. can’t D. can
一、用can, may, must, need, have to, had better的适当形式填空：
1. You ________________ return the library book on time.
2. I ______________ (not) find the way to the hospital. _______________ you show me the
3. —________________ I finish the work right now?
— No, you ________________ (not). You ____________ do it later.
4. He said he ________________ (not) come tonight.
5. Her mother was ill. She ________________ stay at home and look after her.
6. It’s time for class. You ________________ stop playing football or you __________be late
7. We ________________ start right now, or they would get there first.
8. The cloud is lifting, so it ________________ (not) be a rainy day tomorrow.
（ ）1.—Do we have to finish our homework this afternoon?
—Yes, you ________.
A. must B. can C. may D. need
（ ）2. —Must I be in hospital for a week， Doctor?
A. mustn’t B. needn’t C. must
（ ）3. The desk is not dirty. You _______clean it.
A. mustn’t B. shouldn’t C. needn’t C. can’t
（ ）4. —May I watch TV for a while？
—No, you _______. You have to finish your homework first.
A. shouldn’t B. needn’t C. mustn’t D. won’t
（ ）5.—Is Jessica giving us a speech this evening?
—No, it ________be her. She________ to Japan.
A. mustn’t; has gone B. mustn’t ;has been C. can’t ;has gone D. can’t ;has been
（ ）6. It’s the library! So you________ know shouting is not allowed here.
A. can B. must C. need D. may
（ ）7. Boys and girls, don’t forget your report . It ______ today.
A. can’t finish B. can’t be finished C. should finish D. should be finished
（ ）8.—Mr Smith must have been to your home this morning.
—No, he ______ ,because he didn’t know my address.
A. couldn’t B. can’t C. mustn’t D. may not
（ ）9. —Must I mop up the window now?
A. needn’t B. can’t C. shouldn’t D. mustn’t
（ ）10. —Is Lucy knocking at the door?
—No. It ________ be Lucy. She is in Japan now.
A. needn’t B. must C. can’t
（ ）11. —Another cup of coffee?
—No, thanks. I _____ be off. Mary is waiting for me.
A. can B. may C. must D. might
（ ）12. —I’m a little tired. Let’s go to the zoo by taxi.
—We take a taxi. It’s not far from here.
A. can’t B. mustn’t C. couldn’t D. needn’t
（ ）13. If the traffic light is red, you ________ cross the road. It’s very dangerous.
A. don’t B. mustn’t C. needn’t D. wouldn’t
（ ）14. —Must I finish watering the flowers now?
A. must B. won’t C. needn’t D. can’t
（ ）15. —I can’t give up smoking, doctor.
—For your health, I’m afraid you ________.
A. may B. can C. have to D. must
（ ）16. It is usually warm in my hometown in March, but it _______ be rather cold sometimes.
A. must B. can C. should D. would
（ ）17. —Our class won the English speaking contest.
—Congratulations! You _______ be very proud of it.
A. can B. need C. would D. must
（ ）18. —Excuse me, where are we going to have our class meeting?
—I’m not sure. Ask our monitor, please. He know.
A. can B. may C. need D. shall
（ ）19. —____________I borrow these magazines?
—Sorry, only the magazines over there can be borrowed.
A. Must B. Would C. May D. Need
（ ）20. If the traffic light is red, you ________ cross the road. It’s dangerous.
A. don’t B. needn’t C. mustn’t D. wouldn’t
( ) 21 John___ come to see us tonight, but he isn't very sure yet.
A. may B. can C. has to D. must
( ) 22 They ___ do well in the exam.
A. can be able to B. be able to C. can able to D. are able to
( ) 23 -May I take this book out?
A. can't B. may not C. needn't D. aren't
( ) 24 You___ go and see a doctor at once because you're got a fever.
A. can B. must C. dare D. would
( ) 25 -Can you speak Japanese?
A. mustn't B. can't C. needn't D. may not
( ) 26 -He___ be in the classroom, I think.
-No, he ___ be in the classroom. I saw him go home a minute ago.
A. can; may not B. must; may not C. may; can't D. may; mustn't
( ) 27-Shall I get one more cake for you, Dad?
-Thanks, but you___, I've had enough.
A. may not B. must not C. can't D. needn't
( A. may B. must C. can D. need
( ) 29 He isn't at school. I think he ___ be ill.
A. can B. shall C. must D. has to
( ) 30 ___ I take this one?
A. May B. Will C. Are D. Do
( ) 31 The children___ play football on the road.
A. can't B. can C. mustn't D. must
( ) 32 You ___ be late for school again next time.
A. mustn't B. needn't C. don't have to D. don't need to
( ) 33 -Must I do my homework at once?
A. needn't B. mustn't C. can't D. may not
( ) 34 His arm is all right. He___ go and see the doctor.
A. has not to B. don't have to C. haven't to D. doesn't have to
( ) 35 He had to give up the plan, ___ he?
A. did B. didn't C. does D. doesn't ( ) 36 They had to walk here, ___ they?
A. mustn't B. did C. didn't D. hadn't ( ) 37 He had better stay here, ___ he?
A. didn't B. don't C. hadn't D. isn't ( ) 38 You'd better___late next time.
A. not to be B. not be C. won't be D. don't be ( ) 39 You'd better ___ your hair ___ once a month.
A. had; cut B. had; cutted C. have; cut ( ) 40 You___ ask that man over there. Maybe he knows the way.
A. had better not to B. had not better C. had better ( ) 41 -Shall we go and visit the History Museum next Sunday? -______________.
A. Here you are B. Sorry, I can't C. Yes, please ( ) 42 -Why don't you ask Mike to go with us? -Thanks, ___.
A. I will B. I won't C. lean ( ) 43 -___ I take the newspaper away?
-No, you mustn't. You____read it only here.
A. Must; can B. May; can C. Need; must ( ) 44 Excuse me. ___ you please pass me that cup?
A. Do B. Should C. Would ( ) 45 ___ you like to have another try?
A. Could B. Will C. Would ( ) 46 -Would you like to go boating with us? -Yes, ___.
A. I'd like B. I want C. I'd like to ( ) 47 You___ worry about your son. He will get well soon.
A. needn't B. can't C. mustn't ( ) 48 The poor man needs our help, ___ he?
A. need B. needn't C. does ( ) 50 -Must we do our homework first? -No, you___. You may have a rest first.
A. mustn't B. needn't C. may not
D. have; cutted D. had better not D. Let me try D. I may D. Must; must D. Must D. Do D. I do D. have to D. doesn't D. can't