情态动词表推测用法总结(整理稿)

情态动词表推测用法总结
（一）情态动词表推测的三种句式
能用于表推测的情态动词：must, can, could, will, would, may, might, should, ought to
1.在肯定句中一般用must (一定)，may（可能），might / could（也许，或许）。

（1）He must/may/might know the answer to this question?
他一定/可能/也许知道这个问题的答案。

（2）It is cold in the room. They must have turned off the heating.
屋里很冷，他们肯定把暖气关了。

2.否定句中用can’t / couldn’t(不可能), may not/might not(可能不)。

（1）It can’t/couldn’t be the headmaster. He has gone to America.
这不可能是校长，他去美国了。

（2）He may not/might not know the scientist.
他也许不认识那位科学家。

3.疑问句中用can/could (能……?)。

（1）Could he have finished the task?
他可能把任务完成了吗？
（2）Can he be at home now?
他现在能在家吗？
注：以上三种句式中情态动词的语气按程度都是依次递减的。

Might, could并非may, can的过去式，而表示语气较为委婉或可能性较小。

（二）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）She must/may/might/could walk miles and miles among the hills without meeting anyone.
她一定/可能/也许会在山里一连走好几英里而遇不到一个人。

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）Mr. Bush is on time for everything .How can ( could ) he be late for the opening ceremony ?
布什先生一向准时，这次开幕式他怎么可能迟到呢？
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。

（3）Can / Could he have gotten the book？
难道他找到书了吗？
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 m oment.
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。

补充强调：推测的句型特点（对某一次的推测句型有两部分：语气和时态）
（1）语气部分：（以下情态动词语气由强至弱）
肯定句：must、may、might（=could）
否定句：can’t（=couldn’t）、mayn’t、mightn’t
疑问句：can、could（语气更加委婉不确定）
（2）时态部分：
be表示对现在的推测
have done表示对过去的推测
be doing表示对正在进行的推测
语气部分写在前时态部分写在后，组合在一起就是推测
（三）几组表推测的情态动词用法
“情态动词＋完成时”是历年高考的热点，在做此类练习时，既需要掌握这一结构的基本用法，又应该仔细体会题干所提供的语言信息，准确理解语言环境和说话人的含义，尤其要注意题干中时态给予的暗示。

1.must have done表示对已经发生的事情的推测，意为“一定，想必”, 句子中表示的是一种肯定的推测。

这种结构一般只用于肯定句，其否定形式是can’t（couldn’t）have done ，表示“不可能，肯定不会”。

例如：
He didn’t hear the phone . He must have been asleep.
他没有听到电话响，他肯定是已经睡着了。

He must have been to Shanghai.
他一定去过上海。

They can’t have gone out , because the light is on .
他们不可能出去，因为灯亮着。

2. can（could）have done表示对过去的时间内可能发生的事情的猜测，can have done 一般只用于否定句和疑问句。

could have done 还可以用于肯定句，常用来表示本来可能完成而实际未完成的动作。

例如：He can’t have finished the work so soon.
这项工作他不可能完成得这样快。

We could have walked to the station , it was so near .
我们本来是可以走到车站去的，路很近。

3. may（might）have done
（1）表示对已经发生的事情的不太肯定的推测，意为“可能已经，或许已经”。

（2）虚拟用法表示本可以做，但却没做（表示很委屈地责备）
If we had taken the other road , we might have arrived earlier.
如果我们选择另一条路，我们可能会到得早一些。

He might have given you more help, he was very busy.
他本来是可以给你更多帮助的，尽管他很忙。

4. needn’t have done 指实际上做了本来不必要做的事，意为“本来不必”。

例如：
There was plent y of time . She needn’t have hurried.
时间很充裕，她本不必匆忙。

You needn’t have told him the news.
他本来不必把这个消息告诉他。

5. should （ought to ）have done指本该做而实际未做的事，意为“本来应该”。

其否定式shouldn’t（oughtn’t）have done 则表示某种行为不该发生但却发生了。

例如：
You should have started earlier , but you did n’t.
你本应该早一点出发，但是你没有。

You ought to have helped him （but you didn’t ）. 你本应该帮助他。

We shouldn’t have waited for her because she never came.
我们本不应该等她，因为她根本不会来。

6.Would have done 本想做（却没做）wouldn’t have done 本不想做（却做了）
I would have helped you, but I was too busy.
我本想帮你，但我太忙了。

情态动词表示推测专项练习
1. Look! The light is out in her room. She ———— to bed already.
A. must go
B. had to go
C.must have gone
D.has gone
2. We had a wonderful time yesterday. You ———— .Why didn't you come?
A. had to come
B.should have come
C.might have come
D.must have come
3. ─There were already five people in the car but they managed to take me as well.
─ It______ a comfortable journey.
A. can't be
B. shouldn't be
C. mustn't have been
D. couldn't have been
4. My sister met him at the Grand Theatre yesterday afternoon, so he ___ your lecture.
A. couldn't have attended
B. needn't have attended
C. mustn't have attended
D. shouldn't have attended
5. I was really anxious about you. You _____ home without a word.
A. mustn't leave
B. Shouldn't have left
C. Couldn't have left
D. needn't leave
6. Oh, I’m not feeling well in the stomach,I_____ so much fried chicken just now.
A. shouldn’t cut
B. mustn’t have eaten
C. shouldn’t hav e eaten
D. mustn’t eat
7. Mr.White _____ at 8:30 for the meeting, but he didn’t’ show up.
A. should have arrived
B. should arrive
C. should have had arrived
D. should be arriving
8. You ______ be tired - you've only been working for an hour.
A. must not
B. won' t
C. can' t
D. may not
9. - Isn' t that Ann's husband over there?
- No, it _______ be him -I'm sure he doesn't wear glasses.
A. can't
B. must not
C. won't
D. may not
10. There ____ be any difficulty about passing the road test since you have practised a lot in the driving school.
A . mustn’t B. shan’t C. shouldn’t D.needn’t
11. I was on the highway when this car went past followed by a police car. They ______ at lease 150 km an hour.
A. should have been doing
B. must have been doing
C. could have done
D. would have done
12. He _____ have completed his work; otherwise, he wouldn’t be enjoying himself by the seaside.
A. should
B. must
C. wouldn’t
D. can’t
13. ---- The woman biologist stayed in Africa studying wild animals for 13 years before she returned.---- Oh, dear! She _______ a lot of difficulties!
A. may go through
B. might go through
C. ought to have gone through
D. must have gone through
14. This cake is very sweet. You __________ a lot of sugar in it.
A．should put B．could have put C．might put D．must have put
15. —Catherine, I have cleaned the room for you.
—Thanks. You it. I could manage it myself.
A．needn’t do B．needn’t have done C．mustn’t do D．shouldn’t have done
16.—Tom is never late for work. Why is he absent today?
—Something ________ to him.
A．must happen B．should have happened
C．could have happened D．must have happened。