Model verbs 情态动词 情态动词本身有一定的词义，但需与动词原形一起使用， 给谓语动词增添情态色彩，表示说话人对有关行为或事物的态度和看法， 认为其可能，应该或必要等。 情态动词后面通常加动词原形。 A1 can and cannot 情态动词can 与cannot 我们用can 表示某人具备某种能力做某事。 如： I can play basketball.
We can finish the work in 20 minutes. 其否定形式为cannot 或can’t . 如: I cannot swim.
I’m afraid I can’t think of more examples to support this argument. 疑问句中， 把can 提到句首， 将can 与主语的位置对调。 Can you speak any foreigner languages ?
— Can you solve this Maths problem ? — I’m sorry, I can’t
A2 may and may not 情态动词may 与may not
在请求对方的许可， 或是准许你做某事时， 常用情态动词may 和can. may 比较正式，can 较常用且更口语化一些。 如：
— May I leave work early today? — 我今天可以早点下班吗？ Yes, may — 你可以 — You
No, may not — 你不可以
— Can I open a window ? — 我可以开扇窗吗？
Yes, can — 你可以 — You
No, can’t — 你不可以 You may / can use my dictionary. 你可以用我的词典。 You may not/ cannot use my computer. 你不可以用我的电脑。 A3 must and must not 情态动词 must 与must not
must 用以表示“必须做某事” 或“一定要做某事”， 具有强制性， 表达一种责任或义务或表示很有必要做某事； 或在提出建议时使用， 意为“应该； 得”。 如: We must obey the school rules.
The windows are very dirty. I must clean them.
We must go to the bank today. We haven’t got any money. It’s a fantastic film. You must see it.
must 的否定形式是mustn’t, 表示“禁止”， “决不允许”，具有强制性。 如:
I must hurry, I mustn’t be late. You mustn’t forget to phone Julia.
must 用于一般疑问句中，其肯定和否定回答应引起我们的注意。
— Must I go now ? — 我们现在一定要走吗？ Yes, must — 是的； 我们一定要走
— we
No， mustn’t — 不， 我们不可以走。
— Must I finish reading the book this week ? Yes, must — you No, needn’t
典型例析
（ ） 1. — _________ your American friend eat with chopsticks ?
—Yes, but he can’t use them well. A. Can B. Should C. Must
【解析】 A 本句表示能力“ 会； 能够”， can 符合题意。
（ ） 2. Everyone ________ go through the security check (安检) when entering
the World Expo Park.
A. can B. may C. must D. ought 【解析】 C 本句表示“必须， 一定要”， must 符合题意。
（ ） 3. — The winners of the race is a tall and thin boy with glassed.
—Then it _______ be my friend, Mike, who looks very fat. A. might B. can’t C. don’t D. Should
【解析】 B 由上下文语境可知本句的意思是“那么他不可能是我的朋友”， 表推测“不可能”时用“can’t”
( ) 4.— Must I go to the shop with you , Mum?
— Err… I can make it myself, Mike. You ______ go with me.
A. mustn’t B. shouldn’t C. wouldn’t D. needn’t
【解析】 D 由上下文语境可知本句的意思是“ 你没必要去”， 表示“不必要”
可用needn’t 或don’t have to
( ) 5. — This desk is too heavy. I _______ move it. Could you help me ? —
No problem
A. can B. can’t C. should D. shouldn’t 【解析】B 句意为“这桌子太重， 我没法移动它。” 表示“没能力做某事”应
用can’t
( ) 6. — Must I finish my homework right now 、
— No，you _________.
A. needn’t B. may not C. mustn’t D. can’t
【解析】 A 此处must 提问表示“必须” ， 否定回答只能用needn’t 或don’t have to .
( ) 7. — ________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
【解析】D 句意： “ 我可以在大厅里照相吗？” “ 不， 不可以”。 表示请求许可时用can 或may, 其否定回答用can’t 或mustn’t ( ) 8. — _________ I use your ruler, Lingling?
— Sure. Here you are.
A. May B. Would C. Need D. Must
【解析】A 根据句意“用一下你的尺子可以吗？” 可知此处是表示请求许可， 可用may 和can.
考点专练
一 用can , may 或must 的适当形式填空。 1. __________ I ask you a question ? 2. Attending a ball ________ be exciting.
3. Michael _______ be a policeman, for he’s much too short. 4. — Are you coming to Jeff’s party?
— I’m not sure. I _______ go to the concert instead. 5. He never takes a taxi. He _______ be very poor.
6. I thought you ________ like something to read, so I have brought you some books.
7. Look! I __________ stand on my hands.
8. He ______ have been to Shanghai. He knows so well about Shanghai. 9. The play is not interesting. I really _________ go now. 10. She______ like this place. 11. — Could I take this seat, sir? — Yes, you _________.
12. It ________ be very hot in Shengyang in summer.
13. I have just met her in the supermarket. She ______ be in Shanghai now. 14. Mary _________ phone. If she does, could you ask her to ring later? 15. ______ you be happy and healthy. 16. We _______ spit in public.
二 选择正确的情态动
1.Baby _______( can, cannot) run.
2. Dogs _________( can, cannot) understand simple orders. 3词。
1. A b. John practices running every day , so he ___________( can,, cannot) run very fast.
4. You ___________( can, cannot) pass the test if you don’t work hard. 5. Camels ___________( can, cannot) live in the hot areas.
6. Camels ___________( can, cannot) go without water for a long time.
三 根据所给情景，仿照例句写出问句。
1. The radio is very loud, and you and your brother are studying. A: May we turn off the radio? B: Yes, please turn it off.
2. You and your friend see some lost tourists.
A: _____________________________________________________ B: Oh, yes, please help us.
3. You see four of your friends playing basketball.
A: _____________________________________________________ B: Yes, please join us! We need a fifth player.
4. You want to have some ice cream, but you have no money.
A: ______________________________________________________ B: Of course you can borrow 20 yuan.
5. It’s quite hot in the room, and the air conditioner is off.
A: ______________________________________________________ B: Yes, you can turn it off.
6. You ‘d like to order some dishes in a restaurant.
A: ______________________________________________________ B: Yes, of course you can have the menu.
7. You don’t know an English word when you are reading.
A: _____________________________________________________ B: Yes, please use my dictionary.
四 用 you must 或you mustn’t 完成下面的句子。 1. __________________ study hard before your exams.
2. _________________ park your car here. It’s against the rule. 3. _________________ eat more healthy food.
4. ________________ wear a thick coat when it is cold. 5. ________________ swim after a heavy meal.
6. _______________ do some warm –up exercises before going to swim.
五 用适当的情态动词填空。 1. ________I come in ?
2. I _____ speak a little French.
3. _________ I have a look at your pictures? 4. The child ________ ride a bike .
5. The red light is on. We _______ stop. 6. ________ she finish it in three hours?
7. I________ drive a car, but I will learn to drive when I grow up. 8. You ______ borrow three books at a time.
六 用must, mustn’t, may, may not , can 或can’t 填空。