语法专题

情态动词的用法情态动词的用法

情态动词的基本用法特点

1 ） 情态动词 除 ought 和 have 外，后面只能接动词

原型。2 ） 情态动词没有人称，数的变化，即情态动词第 三人称单数不加 -s 。3 ） 情态动词没有非谓语形式，即没有不定式，分 词，等形式。

高中阶段都学过哪些情态动词呢1 can / could / be able to

2 may/might

3 must / have to

4 shall / should

5 will / would

6 need / dare

7 ought to

1 can / could / be able to

1 Some of us can use computers now, but we couldn't last year. （能力）2 It will be sunny in the day time ,but it can rain later on this evening （客观可能性）3 ---Can I go now ? yes ,you can （请求和允许）4 Could you wait a few days for the memory?（请求）5 1 Can this news be true? 2 It can't be our headmaster.he has gone to Beijing. （表推测，主要用于否定和疑问）

*be able to 能用于各种时态。 can / could 只能表示现在或过去的能力。 *was / were able to : “ 设法做成某事” 相当于 managed to do sth.

succeeded in doing sth. 。

1. can 与 be able to 有何区别？

1. A computer ______ think for itself; it must be told what to do. A. can’t B. couldn’t C. may not D. might not2. The fire spread through the hotel very quickly but everyone ______ get out. A. had to B. would C. could D. was able to

A

D

3. They will ______ run this machine on their own in three months.A. can B. could C. may D. be able to

D

2 may / might1 May I watch Tv after supper? Yes you may /No ,you mustn't. （请求许可 )2 It may be true ./ she may come tomorrow/ He might have some fever （推测）3 May you succeed ! May you have many more days as happy as this one （祝愿）

may/ might as well 还是 ----- 好we may as well stay where we are

5. — Could I borrow your dictionary?

— Yes, of course you _______.

A. might B. will C. can D. should

6. — Might I watch TV after supper?

— Yes, you ________.

A. may B. must C. might D. can

C

A

3 must 语 have to 的 用法1 You must come to school on time .You mustn't waste any more time （必须 , 禁止）

2 Must I come back before ten ? Yes ,you must. No, you needn't./ don't have to

3 It must be our headteacher. You must be hungry after a long walk. （推测 )

4 I really must go now. I have to go now,because my mother is in hospital.( 不得不）

He must be reading, ____ he?

You must do it yourself, ____ you?

He must have gone over the article, ______he?

It must have rained last night, _____ it?

3 、表推测语气的反意疑问句的构成isn’t

don’t

hasn’t

didn’t

另外 must 还有偏偏一定要的意思why must you play the piano while othersare sleeping.

7. 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

8. 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

C

B

9. --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

10. --May I pick a flower in the garden?

-- ________.

A. No, you needn’t B. Not, please.

C. No, you mustn’t D. No, you won’t

B

C

4 shall 与 should1 用于一，三人称疑问句表示征求对方的意见和 向对方请示 Shall the driver wait ?What shall we do next ?

2 用于 二 三人称陈述句表示命令警告，允诺，威胁以及法律条文规定You shall go with me / He shall be punished You shall have the book when I finish itAll the children shall go to school at the age of seven.

3 表示劝告和建议You should study hard.

4 表推测They should have arrived by two o'clock

5 用于 if 条件句表示万一Ask Tom to ring me up if you should see him.Shoud I be free tomorrow ,I will come.

6 表竟然I don't know why you should be so rude to your mother

Tom’s father promised, “You ___have a new computer if you pass the coming examination,”

A.can B.should

C.shall D.may

C

------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

B

• You ought to have helped him with his English, ____you ?

• A. won’t you

• B. ought not you

• C. shouldn’t you

• D. wouldn’t you

C

5 will 与 would 的用法1 表示意志和意愿I will never do it again.They said that they would help us.

2 表请求，建议Will you please take a message for me?Would you please pass him the book?

3 表功能This machine won't work.

4 表示习惯性动作与 used to 有何区别Fish will die without water.Every evening ,he would sit by the window.

6 need 语 dare 的用法既可做实意动词又可做情态动词。做情态动词用于否定和疑问句而做实意动词可用于肯定，否定疑问

How dare you say such a thing?

How dare you to say such a thing?

He daren’t to speak English before such a crowd, did he?

He daren’t speak English before such a crowd, dare he?

She _____out alone at night. ( )

A.dare not to go B. dares not go C. doesn’t dare to go D. doesn’t dares go

C

7 ought to 的 用法

1 表应该与 should 的 区别You ought to take care of him.

You are his father .You ought to get him to receive good education

2 表推测He ought to be home by now.He must be home by now.

一 情态动词 + 完成时表对过去的推测1 must have done （仅用于肯定句 )2 can't /couldn't have done( 用于否定疑问句）3 may have done （肯定，否定均可 )4 might have done （肯定，否定均可 )

二 表虚拟1 should / could /would /might have done

三 needn't have done would rather have done had better have done

Jenny ____with him at that time, for I was having dinner with her in my home. ( )

A.can’t have been B. mustn’t have been C. must be D. may be

A

They are 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

D

---- Did you walked home by yourself last night ?

---- Yes, I did. But I think I _____. ( )

A. needn’t B. shouldn’t

C. may not have D. needn’t have

D

• 8. We______last night, but we went to the concert instead.

• A. must have studied B. might study

• C. should have studied D. would study

• 9. There was plenty of time. She_____.

• A. mustn’t have hurried B. couldn’t have hurried

• C. mustn’t hurry D. needn’t have hurried

• 10. Yesterday, Jane walked away from the discussion. Otherwise. She____something she would regret later.

• A. had said B. said

• C. might say D. might have said.

C

D

D

• 11. ----Did you scold him for his mistake?

• ----Yes, but______it.• A. I’d rather not do• B. I’d better not do• C. I’d better not have done• D. I’d rather have not done

D

HomeworkFinish off the exercises.

Read the passage about the modal verbs.