1.肯定推测

能用于肯定推测的情态动词：must, may, might, could

语气强弱程度：must表示“一定”，语气最强；may和might表示“有可能，大概”， 相当于perhaps，其中might语气比may稍弱；could语气最弱，表示“或许”，相当于possibly

1对现在或将来事情的推测，结构为：must/may/might/could+动词原形

例You have worked hard all day. You must be tired. 你辛苦干一整天，一定累了。

Jack knows her. He may/might know her address. 杰克认识她。他可能知道她的地址。

That could be harmful. 那或许是有害的。

考—What are you doing this Saturday?

—I’m not sure, but I ______ go to the Rolling Stones concert.（重庆高考）

A. must

B. would

C. should

D. might

选D。句意：——本周六你打算做什么？——说不准，不过或许我会去滚石乐队演唱会。本题考查情态动词的用法。根据答语中“I’m not sure”可知是对将来不太肯定的推测，故选D项。must表示推测时，语气最强，意为“肯定，一定”；would表过去将来或表意愿；should意为“应该”。

2 对现在正在发生的事情的推测，结构为：must/may/might/could be doing sth.

例The lights in his office are on. He must be working there. 他办公室的灯亮着，他一定在办公室工作呢。

3 对过去事情的推测，结构为：must/may/might/could have+动词原形

例The ground is all wet. It must have rained last night. 地面全湿了。昨天晚上一定是下雨了。

2.否定推测

能用于否定推测的情态动词：can, may, might, could

语气强弱程度：can’t表示“不可能”，语气最强；may not和might not表示“可能不会”，语气较弱；could not 语气最弱，表示“或许不会”

1 对现在或将来事情的推测，结构为：can’t/may not/might not/could not+动词原形

例Your answer can’t be right. 你的答案不可能是对的。

2 对现在正在发生的事情的推测，结构为：can’t/may not/might not/could not be doing sth.

例I saw her go downstairs just now. She can’t be studying in her room. 我刚刚看见她下楼了，所以现在她不可能在房间里学习。

3 对过去事情的推测，结构为：can’t/may not/might not/could not have done sth.

例He has gone abroad. He can’t have attended the meeting last Friday. 他已经出国了，不可能出席上周五的会议。

3.疑问推测

能用于疑问推测的情态动词：can, could

1 对现在或将来事情的推测，结构为：can/could+主语+动词原形

例Can he be an engineer? 他会是一个工程师吗？

2 对现在正在发生的事情的推测，结构为：can/could+主语+be doing sth.

例Can she be watching TV at home? 她会在家里面看电视吗？

3 对过去事情的推测，结构为：can/could+主语+have done

例Can they have won the football games last Sunday? 他们会赢了上周五的足球比赛吗？

情态动词用于推测语气的助记顺口溜：

“肯不肯， 妈妈肯，妹不问”。即：can（谐音“肯”）不用于肯定式； must（谐音“妈”）仅用于肯定句； may/might（谐音“妹”）不用于疑问句，仅用于否定句和肯定句。

EXERCISE

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

A. can

B. may

C. must

D. could

2.—Hi, Tom. Any idea where Jane is?

—She ______ be in the classroom. I saw her on the playground just now.

A. mustn’t

B. can’t

C. may not

D. might not

3.David ______ Beijing now. He has gone abroad.

A. can’t tour

B. couldn’t tour

C. can’t be touring

D. mustn’t be touring

4.My book has disappeared. Who ______ it?

A. must take

B. could take

C. must have taken

D. could have taken

5.He ______ the test again, because he looks upset.

A. must fail

B. must have failed

C. can’t fail

D. can’t have failed

答案

01-05 CBCDB