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。 Couldn’t 比can’t 语气弱一些。
（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.对目前或一般情况的推测，用“情态动词 + be”或“情态动词 + 动词原形”。
（1）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.对正在发生动作的推测，“情态动词 +be doing”
（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。
4.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？
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。
.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。
一、单项选择
1 John___ come to e us tonight, but he isn't very sure yet. A. may B. need C. can’t D. must
2 John isn’t in the classroom. He ___ play soccer on the playground with Bob. A. can B. must C. should D. can’t
3 -Will you go to the cinema with us? -No, I ___ rather read a magazine at home.
A. should B. might C. would D. had better
4 You___ go and e a doctor at once becau you got a fever. A. can B. must C. dare D. would
5 -Can you speak Japane? -No, I____. A. mustn't B. can't C. needn't D. may not
6 -He___ be in the classroom, I think. -No, he ___ be in the classroom. I saw him go home a minute ago.
can; may not B. must; may not C. may; can't D. may; mustn't
7 -Is Lena swimming in the pool? -No, she ___ swim. She is terrified of water. A. may not B. must not C. can't D. needn't
8 He isn't at school. I think he ___ be ill. A. can B. shall C. must D. might
9 -What do you think “upt” means? - I’m not sure. It ___ mean “sad”. may B. must C. can D. should
10 The children___ play football on the road. A. can't B. can C. mustn't D. must
二、根据句子意思用must, might, could或can’t填空
1. The white ruler______________ belong to Lucy. Hers is red.
2. I can’t find my keys. They ______________ be still at home.
3. The exerci book______________belong to Bob. It has his name on it.
4. Jim______________ be at home. He has gone to his hometown.
5. This blue shirt ______________ belong to Ken. He likes blue best.
6. The schoolbag ______________ be Paul’s. There are a lot of books in it.
7. The volleyball______________ belong to Alice. She plays volleyball every day.
8. The classroom is clean. Someone ______________ clean it just now.
9. –Is that Bob there? –No, it ______________ be him. He has gone to Shanghai with his family
10. –where is Mr. Lee? –The light in his bedroom is still on. He __________ be there.
11. I ______________ find my pencil ca. I think I have lost it.
12. The boy is clever. He ______________ tell many stories when he was young.
13. The man is running fast. He______________ be catching the bus.
14. Li Lei has learned English for 15 years. He ______________ know the meaning of this ntence.
15. –What are you going to do this weekend ? –I’m not sure. I ______________ visit my grandparents.
16. –Who is that boy in blue?
–It______________ be Tim. He is always reading English there every morning.
–It______________ be him. He is talking with Miss Liu in the classroom.
