情态动词 ㈠ can的用法 may的用法 must的用法.

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1 情态动词 ㈠ can的用法 may的用法 must的用法

2 can的用法 ㈠. 1.能力 2.许可 3.猜测（用于疑问句、否定句） ㈡.can与be able to的区别
㈠. 1.能力 2.许可 3.猜测（用于疑问句、否定句） 1.I can lift the stone. 2.You can borrow my bike tomorrow. 3.Can it be true? It can’t be true. ㈡.can与be able to的区别 can有现在时、过去时；可用于被动语态。 be able to有各种时态；指某一次动作；不可用于被动语态。 1.He says he will be able to be home for Christmas. 2.I was able to help you yesterday. 3.This problem can be settled at once.

3 1.She could have explained the matter. 2.Can she have told a lie?
㈢.常用句型 1. could have done 2. can/could… have done ? 3. can’t/couldn’t have done 本来能够做 可能做过…吗？ 不可能做过 1.She could have explained the matter. 2.Can she have told a lie? 3. Where can/could he have gone? 4.He can’t/couldn’t have said that. 5.She can’t/couldn’t have been at home all this time.

4 1.You may go home now,Susan. 2.You may not smoke in the classroom.
㈠。1.许可 表示许可时，无甚区别，may较正式，can较口语化。 1.You may go home now,Susan. 2.You may not smoke in the classroom. 3.May I sit down? —Certainly./ Yes,please./ Why not?/ Sure. —No, I am sorry./ I’m afraid you can’t. 4.I may borrow this book, mayn’t I? 5.May I speak to you for a moment,professor? 6.Can I have a cup of tea, mother?

5 1.The story may or may not be true. 2.Can that be true?
2.猜测、可能性（用于肯定句中） 1.The story may or may not be true. 2.Can that be true? May that be true? 3.He can’t know the truth. He may not know the truth. 他不可能知道真相。 他可能不知道真相。 ㈡。may have done 可能做过 1.she may have missed the bus. 2.It may have drizzled during the night.

6 must的用法 1.You must get up much earlier.
㈠。1.必须、一定 2 .偏偏 猜测（用于肯定句） 1.You must get up much earlier. 2.You must not speak ill of others. 3.Must we wash the dishes at once/ Yes, you must. No, you needn’t ./ you don’t have to. 4.Our boy must do the opposite to what we ordered. 5Just when I was busy , she must come and chatter. 6.It’s 10 o’clock .My mother must be angry. 7.We thought our teacher must be joking.

7 1.It must have rained last night.The ground is wet.
㈡。must have done 肯定做过 1.It must have rained last night.The ground is wet. 2.No one answers the phone bell.They must have gone out. ㈢。构成的反意疑问句 ⑴。必须—mustn’t/needn’t neednt’t we 1.We must work hard at maths,____________ ? 2.You must realize that we can’t allow such behavior, _____________ ? 3.They must to there at once, _________________ ? 4.The houses must be clean if there are guests, _________ ？ mustn’t you ⑵。有必要—needn’t needn’t they needn’t they

8 ⑶。mustn’t禁止、不许—may/must
5.You mustn’t talk like that ,_____________? 6.Students mustn’t talk during lessons, ______________ ? 7.Mary must be in the room,___________ ? 8.You must live near my friend if you live in the New Street,____________ ? 9.Mike must have studied French ,___________? 10.They must have done their homework yesterday,____________ ? must/may you must/may they ⑷。猜测—与must后的动词一致 isn’t she don’t you hasn’t he ⑸。有过去时间的短语或从句时—didn’t didn’t they

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