（必修）英语3一年级《Theme A Life and Attitude Attitude Unit 2 Parents and Children Grammar》优秀ppt课件

（必修）英语3一年级《Theme A Life and Attitude Attitude Unit 2 Parents and Children Grammar》优秀ppt课件

（3）must表示推测时，可以推测现在/正在发生的动作/过去发生的动作。 He must have a car now. （现在）他一定有辆小汽车。 He must be doing his exercises in the classroom.（正在进行）他一定在教室里做练习。 He must have finished the work.（过去发生）他一定已完成了工作。 注：must表示推测时很少用于将来的情况。一般不用He must come tomorrow.可用It`s certain / I`m sure that he will come tomorrow.

（4）在反意疑问句中，当附属部分含有表示推测意义的must时，疑问部分的助动词应与must后面的动词在非推测情况下的用法保持一致。 He must be a worker, isn`t he? （现在）他准时个工人，是吗？

You must have learned English for many years, haven`t you? （完成时）你一定学了好多年英语，是吗？ 比较：

It must have rained last night, didn`t it? （过去）昨晚一定下雨了，是不是？ He must have arrived by yesterday morning, hadn’t he?

2. can / could的用法 （1）can表示推测“可能性”时，往往用于否定句或疑问句。Can`t“一定不”，can在疑问句中意思是“会、可能”。 He can`t be at home. = It is impossible that he is at home. 他一定不在家。 （2）can /can`t+ have done，表示对过去发生的动作进行推测。 He can`t have gone to Shanghai for I saw him a minute ago. 他不可能去了上海，我刚才还看见他。 It`s so late. Where can she have gone? 天晚了，她可能去哪儿了呢？

（3）could 还可以用于表示客气、委婉、礼貌的请求语气。

Excuse me, could you tell me the way to the bus station? Could you help me? （4）could have done

本能做但未做，表虚拟语气

I could have done it well，but I wasn’t so careful then .

3. may和might的用法 （1） may, might表示推测“可能性”时，意思是“可能”、“也许” He may / might be American. = It is possible that he is American. 他可能是个美国人。 注：might不表示过去时态，只是语气上比may更委婉，表示的可能性更小。 （2）may, might表推测时，可以用于否定句，意思是“可能不、也许不”，但不用于疑问句。 He may / might not be at home. 他也许不在家。

（3）may, might可以推测现在正在发生的动作或过去发生的动作。 He may / might be sleeping now.

The boy may / might not be watching TV at home. 这个男孩可能没在家看电视 These students may / might have seen the film

before.（过去） 这些学生以前可能看过这部电影。

2. –That man must be Sarah’s husband. --No, he_____ be her husband. She is still single. A. can’t B. mustn’t

C. may not D. ought to

3. Peter _____come with us tonight, but he isn’t very sure. A. must B. may C. can D. will

4. –What____ it be? --It______ be a mail box, for it is moving.

It______ be a car. A. can; can’t; must B. can; can; must C. can; mustn’t; must D. must; mustn’t; can

5. –Look, someone is coming. Guess__________ . --Jack. He’s always on time. A. who can it be B. who he may C. who he can be D. who it can be

6. –I saw Mary in the library yesterday. --You_____ her. She is still abroad. A. mustn’t see B. can’t have seen C. mustn’t have seen D. couldn’t see

7. David, you _____play with the valuable bottle, you_______ break it. A. won’t; can’t B. mustn’t; may C. shouldn’t; must D. can’t; shouldn’t

8. Susan refuses to marry Jack now. She ______her mind. A. must change

B. should have changed C. must have changed

D. would have changed

9. Sue________ come together with us tonight, but she isn`t very sure yet. A. must B. may