情态动词表推测

(must/ can/ may/ could/ might)

 

一、肯定句

must＞may＞might/could

1. He must / may / might(could) come from America.

他肯定/可能/也许是美国人。

2. There is still light in his room. He must / may / might (could) be studying at this time.

他房间里还有灯光，他这时一定/可能/也许还在学习。

3. Tom isn’t in the classroom. He must / may / might (could) have gone to the library.

汤姆没在教室里，他一定/可能/也许到图书馆去了。

 

二、否定句

can’t, couldn’t不可能；mayn’t, mightn’t可能不

1. It’s snowing outside. He can’t / couldn’t / may not / mightn’t be on the playground.

外面在下雪，他不可能/可能不在操场上。

2. He knew nothing about the book. He can’t / couldn’t / may not / mightn’t have read it before.

 

三、疑问句

can，could

--- Can he be English?

--- No, He can’t be English. He must be American.

 

四、区别

(一) must; can’t   语气最强，基于观察到的迹象。

1. --- She looks very happy. She ___ have passed the exam.

  --- I guess so. It’s not difficult after all.

  A. should   B. could   C. must   D. might         (C)

2. She ____ have left school, for her bike is still here.

  A. can’t    B. wouldn’t   C. shouldn’t   D. needn’t  (A)

(二) may; might; could   说话人不太确定的推测。

1. Helen ____ go on the trip with us, but she isn’t quite sure yet.

  A. shall   B. must   C. may   D. can         (C)

2. --- Are you coming to Jeff’s party?

  --- I’m not sure. I ____ go to the concert instead.

  A. must   B. would   C. should   D. might  (D)

3. --- There were already 5 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  (D)

(三) should 说话人的期盼

--- When can I come for the photos? I need them tomorrow afternoon.

--- They ___ be ready by 12:00.

A. can   B. should   C. might   D. need  (B)

(四) must用于肯定句；may/might用于肯定句、否定句；can用于否定句、疑问句；could用于肯定句、否定句、疑问句。

 

五、解题技巧

1. 判断句型：肯定句，否定句或疑问句。

2. 判断时间，确定使用什么时态。

3. 判断推测的强弱，确定使用哪个情态动词。

 

六、练习

表示推测的情态动词must、can, could, may, might及其否定式改写下列句子。

1. I am sure she is relaxing in her room.

  She _____ be relaxing in her room.

2. Perhaps the plane arrived late, and that is why they are not here.

  The plane _____ have arrived late, and that is why they are not here.

3. Maybe they lied to me about their adventure.

  They ____ have lied to me about their adventure.

4. It is possible that Sam doesn’t like classical music.

  Sam _____ like classical music.

5. I do not believe you failed the exam.

  You _____ have failed the exam.

6. It is quite probable that Bill did not win the competition.

  Bill _____ have won the competition.

7. I’m sure John is not forty-five yet.

  John _____ be forty-five yet.

答案：

1. must     2. may/might/could   3. may /might/could   

4. may not/might not      5 couldn’t/can’t     6. couldn’t/can’t     7. can’t