must和need相同:Yes,... must. No,... needn't/don't have to
may和can could相同:Yes,... may/can/could. No,... mustn't/...'d better not/can't.
shall:Yes,... can/may. No,... can't.
should:Yes,... should. No,... shouldn't.
will和would差不多:Yes,...do/will. No,...won't/thanks.
情态动词的回答方式
问句 肯定回答 否定回答
Need you…? Yes, I must. No,I needn't
Must you…? /don't have to.
典型例题
1)---Could I borrow your dictionary?
---Yes, of course, you____.
A. might B. will C. can D. should
答案C.could表示委婉的语气,并不为时态。答语中of course,表示肯定的语气,允许某人做某事时,用can和 may来表达,不能用could或might。复习: will 与you连用,用来提出要求或下命令。should与you 连用,用来提出劝告。
2)---Shall I tell John about it?
---No, you ___. I've told him already.
A. needn't B. wouldn't C. mustn't D. shouldn't
答案A。needn't 不必,不用。 wouldn't 将不, 不会的。 mustn't 禁止、不能。 shouldn't 不应该。本题为不需要,不必的意思,应用needn't。
3)---Don't forget to come to my birthday party tomorrow.
---______.
A. I don't B. I won't C. I can't D. I haven't
答案B. will既可当作情态动词,表请求、建议、也可作为实义动词表"意愿、意志、决心",本题表示决心,选B。
表示推测的用法
can, could, may, might, must 皆可表示推测,其用法如下:
1)情态动词+动词原形。
表示对现在或将来的情况的推测,此时动词通常为系动词。
I don't know where she is, she may be in Wuhan.
2)情态动词+动词现在进行时。
表示对现在或将来正在进行的情况进行推测。
At this moment, our teacher must be correcting our exam papers.
这时,我们老师想必在批改试卷。
3)情态动词+动词完成时。
表示对过去情况的推测。
We would have finished this work by the end of next December.
明年十二月底前我们很可能已完成这项工作了。
The road is wet. It must have rained last night.
地是湿的,昨天晚上一定下雨了。
4)情态动词+动词的现在完成进行时。
表示对过去正在发生事情的推测。
Your mother must have been looking for you.
你妈妈一定一直在找你。
5)推测的否定形式,疑问形式用can't, couldn't表示。
Mike can't have found his car, for he came to work by bus this morning.
迈克一定还没有找回他的车,因为早上他是坐公共汽车来上班的。
注意:could, might表示推测时不表示时态,其推测的程度不如can, may