高中语法专练：ix. “can/may/might/could/must/should/need +完成式”表示对过去情况的推测

ix. “can/may/might/could/must/should/need +完成式”表示对过去情况的推测

1. “must + 完成式”意为“一定，肯定，想必，准是”,表示对过去情况进行有把握的肯定推测。

He speaks English so well, he must have been to England.

他英语说得那么好，一定去过英国。

They must have seen the film before because they know it so well.

他们以前一定看过这部电影，因为他们知道那么多。

注意其反意疑问句的反问形式：

1）有表示过去的时间状语时，用一般过去时进行反问。谓语是must have been用wasn't/weren't反问；谓语是must have done用didn't反问。

They must have attended the meeting yesterday , didn't they ?

昨天他们一定开会了，是吗？

They must have been to America last year, weren't they ？

去年他们一定去过美国，是吗？

2）没有明确的过去时间状语时，用haven't/hasn't反问。

They must have attended the meeting, haven't they ?

他们一定参加了那次会议，是吗？

They must have been to America, haven't they ?

他们一定去过美国，是吗？

2. “can't/couldn't +完成式”意为“肯定没有”，表示对过去情况进行否定推测。

She can't have gone to school, for it is Saturday today.

她肯定没上学去，因为今天是星期六。

She couldn't have heard you knocking at the door.

她肯定没有听见你敲门。

注意：

1）“can +完成式”，一般只用于进行否定或疑问的推测。

There is no light in the room, can he have gone out？

房间里没有灯光了，他可能出门了吗？

2）“could+完成式”也表示过去能做而没有做的事，有惋惜之意。

I could have done it better, but I had no time left.

我本来能够做得更好，但我没有时间了。

He could have helped you, why didn't you ask him for help?

他本来能够帮助你的，你为什么不请他帮忙呢？

3. “may+完成式”意为“有可能已经发生某事”，只用于对过去发生的事情进行肯定的推测。

I think he may have gone to bed.

我想他有可能已经睡觉了。

She may have missed her train.

她有可能已经错过了火车。

4. “might +完成式”与“may +完成式”，二者可互换，但是might所表示的可能性较小。

—What do you think that noise was?

—It might have been a cat.

——你认为那噪音是什么？

——那或许是一只猫。

It's ten o'clock, she might have gone to bed.

现在十点钟了，她或许已经睡觉了。

注意：

might也可表示对本来可能发生却未发生的情况感到不满或责备。

If we had taken the other road, we might have arrived.

如果我们走另一条路，我们本来可能已经到了。

You might have told us earlier.

你本来能早一点告诉我们的。

5. “should/ought to +完成式”，意为“本应该”，可以表示以下两种含义：

1）过去应该做而没做到某事，其否定式表示过去不该做而做了，有遗憾或责备之意。

You should have come here five minutes ago.

你本应该五分钟前就到的。

We ought to have given him more help.

我们本应该给他更多的帮助的。

You shouldn't have told him the news. He is crying now.

你本不应该告诉他这个消息的，他现在在哭呢。

You oughtn't have gone to the football match.

你不应该去看足球的。

2）表示对现在应该完成的事情进行推测。

He ought to have arrived by now.

到现在他应该到了。

They should have finished the work by now.

到现在他们应该完成了工作了。

6. “needn't +完成式”，表示本来不需要做某事却做了。

He needn't have gone to the railway station yesterday.

昨天他本来没有必要去火车站的。

I needn't have bought all the wine—only three people came.

我本来没有必要买这么多酒，只来了三个人。

You needn't have watered the flowers, for it is going to rain.

你本来没有必要给花浇水的，因为天要下雨了。

专项练习

1. —You didn't hear me until now.

—No. I must _______ soundly when you came in.

A. have been sleeping

B. have slept

C. be sleeping

D. sleep

2. Her father thought that she _______ a fairy.

A. must have met

B. had to have met

C. must meet

D. must had met

3. He must have lost the key the day before yesterday, _______?

A. must he

B. hasn't he

C. needn't he

D. didn't he

4. They _______ have gone out because the light is on.

A. mustn't

B. can't

C. may not

D. isn't able to

5. We didn't see him at the lecture yesterday. He _______ it.

A. oughtn't

B. can't have attended

C. couldn't attend

D. needn't have attended

6. She is very careful. How _______ she _______ such a mistake the day before yesterday?

A. could; have made

B. should; have made

C. could; has made

D. can; made

7. He is my good friend. I am sure that he _______ ill of me that day.

A. couldn't have spoken

B. mightn't have spoken

C. must have spoken

D. couldn't have to speak

8. I was writing my report last Sunday. Otherwise, I _______ you to the zoo.

A. would take

B. took

C. should take

D. could have taken

9. —Have you found your book yet?

—No, I'm not sure where I _______ it.

A. must have left

B. might leave

C. could have left

D. can leave

10. He _______ the truth. Otherwise he might have known it was Tom who had taken his place.

A. should have been told

B. shouldn't have been told

C. couldn't have been told

D. must have been told

11. Mr. Bush is on time for everything. How _______ it have been that he was late for the opening ceremony?

A. could

B. should

C. may

D. must

12. —I stayed at a hotel while in New York.

—Oh, did you? You _______ with Barbara.

A. could have stayed

B. could stay

C. would stay

D. must have stayed

13. He _______ you more help, even though he was very busy.

A. might have given

B. might give

C. may have given

D. may give

14. —He was here yesterday, but no one has seen him since.

—He _______ an accident.

A. might have

B. might have had

C. can have

D. mustn't have had

15. You were stupid to try climbing up there. You _______ yourself.

A. might have killed

B. should have killed

C. must have killed

D. can't have killed

16. The plant is dead. I _______ it more water.

A. will give

B. would have given

C. must give

D. should have given

17. I told Sally how to get here, but perhaps I _______ for her.

A. had to write it out

B. must have written it out

C. should have written it out

D. ought to write it out

18. That young man has made so much noise that he _______ not have been allowed to attend the concert.

A. could

B. must

C. would

D. should

19. There was a lot of fun at yesterday's party. You _______ come, but why didn't you?

A. must have

B. should

C. need have

D. ought to have

20. I'm sorry. I _______ to tell you I was coming.

A. ought to phone

B. should phone

C. need to phone

D. ought to have phoned

21. We _______ the letter yesterday, but it didn't arrive.

A. must receive

B. ought to receive

C. must have received

D. ought to have received

22. When I got to the cinema, the film had already started; I _______ there earlier.

A. ought to get

B. ought to have got

C. must have got

D. must get

23. The old lady _______.

A. ought to apologize to

B. ought to be apologized to

C. ought apologize to

D. ought be apologized to

24. You oughtn't to have helped him with his English, _______?

A. won't you

B. ought not you

C. oughtn't you

D. wouldn't you

25. Although he had made many mistakes in his composition, _______ have laughed at him?

A. oughtn't we

B. should we

C. oughtn't to we

D. ought to we

26. He didn't do well in the exam. He _______ hard at his lessons.

A. must have worked

B. ought to have worked

C. would have worked

D. has worked

27. —I didn't go to see a doctor yesterday.

—But you _______.

A. ought to

B. ought to go

C. should

D. ought to have

28. He began to write two hours ago. He _______ have finished the article by now.

A. must

B. ought to

C. ought

D. had to

29. One ought _______ for what one hasn't done.

A. not to be punished

B. to not be punished

C. to not punished

D. not be punished

30. He _______ the meeting, so he stayed at home.

A. needn't have attended

B. didn't need to attend

C. didn't need attend

D. needn't to have attended

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