情态动词表推测的用法小结

（一）

情态动词表推测的三种时态

1.对将来情况的推测，用“情态动词 + 动词原形”。

（1）She must / may / might / could arrive before 5. 5:00前她一定/可能/也许到

2.对现在或一般情况的推测，用“情态动词 + be”，“情态动词 +be doing”或“情态动词 + 动词原形”。

（1）He must / may / might / could be listening to the radio now.

他一定/可能/也许正在听收音机。

（2）He can’t ( couldn’t ) / may ( might ) not be at home at this time.

这个时候他不可能/可能不在家。

3.对过去情况的推测，用“情态动词 + have +过去分词”。

（1）It must / may / might / could have rained last night .The ground is wet.

地湿了，昨晚肯定/可能/也许下雨了。

（2）The door was locked. He can ( could ) not / may ( might ) not have been at home . 门锁着，他不可能/可能不在家。

注：情态动词 should /ought to表推测时，意为“想必会，理应……”但与“have +过去分词”连用时，则又可构成虚拟语气意为“本应该做某事却没做”。例如：

（4）It’s seven o’clock. Jack should/ought to be here at any moment.

现在七点钟了，杰克理应随时到达。（推测）

（5）She should / ought to have attended your birthday party, but she had to look after her mother in hospital. （虚拟） 她本该出席你的生日晚会的，可是她得在医院照顾她妈妈。

（6）Tom should not /ought not to have told me your secret, but he meant no harm. （虚拟）

汤姆本不该告诉我你的秘密，可是他并无恶意。

重点疑难

（一）need和dare的用法

need和dare既可用作情态动词，也可用作实义动词。用作情态动词时，主要用于否定句和疑问句。用作实义动词时，可用于各种句式。

1.用作情态动词

--Need I come? --Yes, you must. --我需要来吗？ --需要。

She dare not go out alone at night. 她晚上不敢一个人出去。

How dare you say I′m unfair? 你竟敢说我不公平？

Not one of them dared mention this. 他们谁也不敢提这件事。

2.用作实义动词

You don′t need to do it yourself. 你不必亲自做这件事。

We need to tell them the news. 我们需要把这消息告诉他们。

The table needs painting (to be painted.). 桌子需要油漆一下。

We should dare to give our own opinion. 我们要敢于提出自己的观点。

（二）情态动词后跟完成式和进行式的用法

1.情态动词后跟完成式，表“应当已经……”，“想必已经……”，“本来可以……”等意。 I should have finished the work earlier. 我应当早一点完成这项工作的。

He isn′t here. He must have missed the train. 他还未到，一定是没赶上火车。

You could (might) have been more careful. 你本来可以更细心的。

He needn′t have worried about it. 他本不必为此事担心。

2. 情态动词后跟进行式，表示“想必正在……”，“可能正在……”，“应当正在”等意。 It′s twelve o′clock. They must be having lunch. 现在是十二点。他们一定正在吃饭。 They may be discussing this problem. 他们可能正在论讨这个问题。

He can′t be telling the truth. 他说的不可能是真话。

（三）几组词的辨异

1. can 和be able to

1）情态动词can只有两种时态形式，现在式can和过去式could，而be able to有多种时态形式。

Mary can play the piano. She has been able to play it since she was 5.

玛丽会弹钢琴。她五岁起就会弹了。

2）用在过去时中，could经常表示能够做某事，事实上不一定去做，而was∕were able to则表示“过去做成了某事”。在否定句中两者可通用。

He could swim across the English Channel. But he didn′t feel like it that day.

他能游过英吉利海峡，但那天他不想游。

2. must和 have to

must表示主观意志，而have to表示由于客观因素不得不做某事。must没有过去式，除在间接引语中可用于表示过去时间，在直接引语中表示过去时间应该用had to代替。 I told her that she must give up smoking. 我叫她必须戒烟。

We had to get everything ready that night. 我们那晚得把一切准备就绪。

3. would和used to

1）used to表示过去与现在或过去某时与后来的情况有不同，而would只表过去的情况。People used to think that the earth was flat.

过去人们认为地球是平的。（现在人们不这么认为。）

She would go out for a walk in the morning when she was in the country.

在乡下时，她总是在早晨去散会儿步。（可能现在仍有散步的习惯。）

2）used to可表示过去的习惯动作和经常的情况，而would只表示过去的习惯动作。 He used to ∕would smoke while writing. 过去他写东西时常抽烟。

She used to be fat. 她过去很胖

专项练习（二）

have kept his promise. I wonder why he changed his idea.

A. must B. should C. need D. would

2. Jane A. could; could B. might; could C. should; could D. should; would

3. So many mistakes in your homework! You A. may be B. had to C. would be D. should have been

4．Her brother just now. A. mustn’t B. needn’t C. can’t D. shouldn't

5．---I can’t understand why our boss is late. ---He the early bus.

A. could miss B. may have missed C. can have missed D. might miss

6. She didn't answer the phone, she ______ asleep.

A. may be B. must be C. should have been D. must have been

7．The little girl’s eyes were red. She ______.

A. may cry B. must cry C. must be cried D. must have been crying

8．He______ his supper now, for the dining hall is still closed.

A. can’t be having B. needn’t be having C. mustn’t be having D. shouldn't be having

9．I parked my bike behind the building, but now it is gone. It ________ .

A. may be stolen B. must be stolen C. must have been stolen D. must have stolen

10. ______ Mr. Black_______go to work by ferry before the bridge was built?

A. Did; used to B. Use; to C. Did; use to D. Does; use to

11. The hotel is only a stone’s throw away, you ______ take a bus.

A. need not to B. not need to C. don't need D. need not

12. I am busy now, _______ my brother do it for you ?

A. Will B. Shall C. Must D. May

13. ---You needn’t do it right now, need you?---Yes I am afraid I ______ .

A. need B. needn’t C. must D. mustn’t

14.My English-Chinese dictionary has disappeared . Who _____ have taken it?

A. should B. must C. could D. would

15. ---The room is so dirty._______ we clean it?----Of course.

A． Will B. Shall C. Would D. Do

16. If you have something important to do, you ______ waste any time.

A. needn’t B. mustn’t C. may not D. won’t

17. If you want to borrow a football after school, your student card______ here.

A. has to leave B. must leave C. has to be left D. must be left

18. “ Did you scold him for his carelessness?” “Yes, but _____ it”

A. I’d rather not do B. I’d rather not have done C. I shouldn’t do D. I’d better not do

19. “ Don’t get near to it . It is too dangerous!” “_______” .

A. Yes, I won’t B. No, I don’t C. No, I can’t D. No, I won’t

20. He must be in the classroom, _______ he?

A. mustn’t B. can’t C. isn’t D.can

21. He________ be in the garden. He must be in the room.

A. can’t B. mustn’t C. will not D. may not

22. “Do you have to leave now?” “I am very sorry, but I really______.”

A. can’t B. have C. should D. must

23. “Let’s go to the library, shall we?” “_________?”

A. No, I can’t B. Yes, I will C. Yes , thank you D. No, we’d better not

24. “Can I take it away?” “ You ______ better not.”

A. should B. could C. would D. had

25. You _______ have brought your camera. They all had theirs with them.

A. couldn’t B. needn’t C. wouldn’t D. mustn’t

26. See who is there!______it be May?

A. May B. Must C. Can D. Will

27. John______ be a basketball player. He is much too short.

A. may B. mustn’t C. can’t D. should

28. The Chinese teacher looks so pale. She ______ be ill.

A. must B. mustn’t C. can D. need

29. Something______to save our earth. Do you think so?

A. can do B. must do C. has to do D. must be done

第二篇：情态动词表推测的用法

情态动词表推测的用法

一、must表示推测的用法

must表示推测时，只用于肯定句，表示很大的可能性，意为“一定，准是，必然会”。其否定形式是 can’t/couldn’t (不可能)。例如：

1. You haven’t eaten anything since this morning; you must be hungry.

2. That can’t be Mary — she’s in hospital.

二、can/could表示推测的用法

1. can表示推测时，多用于肯定句和疑问句。当用于肯定句时，指“有时可能会”，是理论上的可能，其时间意义宽泛不具体。例如： Even experienced teachers can make mistakes.

2. could表示推测时，既可以用于肯定句，又可以用于疑问句。 例如： My book has disappeared. Who could have taken it?

3. can’t/couldn’t表示推测时，用于否定句，是语气最强的否定推测，意为“不可能，一定不(是)”。 例如：

He can’t/couldn’t have seen her there.

【即学即练】

一、用表示推测的情态动词must, could, , can的适当形式填空。

1. — Hi, Tom. Any idea where Jane is?

— She be in the classroom. I saw her there just now.

2. — I hear they went skiing in the mountains last winter. — It be true because there was little snow there. 3. Accidents happen on such rainy days.

二、翻译下列句子，注意情态动词的推测用法和情态动词后动词的形式。 —那个人一定是布朗先生。—不可能是他，他去纽约了。

【反义疑问句】又叫附加疑问句。它表示提问人的看法，没有把握，需要对方证实。反义疑问句由两部分组成：前一部分是一个陈述句，后一部分是一个简短的疑问句，两部分的人称时态应保持一致。 如：She was ill yesterday, wasn’t she?

They don’t work hard, do they?