高三英语语法复习之情态动词的用法.doc

情态动词—model verbs
(括号内为过去式):
can(could)能,能够,可能,有时候会; may(might)可能,可以;
shall(should)将会,将要,要不要,必须,必定; will(would)将要,愿意;
must(must)必须,一定,必定; need(need)需要;
ought to= should应该; be able to能,能够;
used to 过去经常; dare(dared)敢; had better最好是
.注意:1)否定式直接在后面加not,但be able to的否定式是be not able to,used to的否定式是used not to/didn’t use to,ought to的否定式是ought not to。
2)dare、need也做实义动词,后跟to do,此时有第三人称单数式dares/doesn’t dare、needs/doesn’t dare, 过去式dared/didn’t dare、needed/didn’t need。
3)be able to do可用于其他情态动词(除had better,dare)之后,此时否定式加在be able to前面,如: will not be able to
4) be able to表示有能力并且做了,而can表示有能力但不一定做。
5) 现在时间状态下,用情态动词的过去式比用现在式语气更委婉、更客气。
6)现在时间状态下,表推测时过去式比现在式语气弱。
二. 功能与特征:
功能:1)表示说话人的语气或情绪 2)表示推测
特征:1)情态动词有一定的含义(而另外三个助动词(have/be/do)没有意义)
2)不能单独作谓语动词,必须和动词原形一起才能构成谓语
3)有过去式,无人称和数的变化
、许可的情态动词的用法:
1)表示能力: can, could, be able to
*be able to 能用于各种时态,如will be able to do; is/are able to do, was/were able to do, would be able to do等,其中was / were able to表示“设法做成某事”,相当于managed to do sth. / eeded in doing sth.。
can 用于现在时态,could用于过去时态,翻译为“能”,还可表示“有时候会”。
Mostly my father is serious, but sometimes he can be funny too.
大部分时候我爸爸都是很严肃的,但有时候他也会很有趣。
1. puter ______ think for itself; it must be told what to do.
A. can’t B. couldn’t C. may not D. might not
2. The fire spread through the hotel very quickly but everyone ______ get out.
A. had to B. would C. could D. was able to
3.