情态动词完成时态的用法(共2页).doc

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1、精选优质文档-倾情为你奉上“情态动词+have done”用法归纳曲靖市第二中学 杨绍斌 情态动词+have done用法例句must have done 表示主观上对过去已经发生的行为进行推测，意为“想必，准是，一定做了某事”She must have gone through a lot.He must have visited the White House during his stay in the United States.may have donemight have done 表示对过去已发生行为的推测，意为“也许/或许已经（没有）” 一般用于肯定句或否定句中，不用于疑问句

2、用might则表示语气更加不肯定You may have learnt the news.He may not have heard his name called.Sorry Im late. I might have turned off the alarm clock and gone back to sleep again.might have done 表示“本来可能，但实际上没有发生的事情”即，推测过去有可能发生但已确知并为发生的事情may have done 没有此用法 另外，还可以表示“本来应该或可以做某事”之意，含有轻微的责备语气；有时也表劝告You should not s

3、wim in that sea; you might have been eaten by a shark. He might have given him more help, thought he was busy.canhave donecannot have done 只用在否定句和疑问句中 表示对过去发生的行为的怀疑和不肯定 can换成could时语气委婉 Where can she have gone? Could he have done such a foolish thing? The boy cant have finished reading the book so so

4、on because it is difficult even to an adult.could have done 可用在肯定句、否定句和疑问句中 表示“可能已经” 还可以表示过去能做而没 做的事，有一种对过去为付诸实施的事情的惋惜 He could have killed himself driving at a dangerous speed.You could have been more considerate.You could have done better, but you were too careless.should/ought to have done 用于肯定句时

5、，表示本该做某事，而实际上未做 用于否定句时，则表示不该做的事反而做了He should have known that the police would never allow this sort of thing.You shouldnt have done it so carelessly.You ought to have returned the book earlier.You ought not to have refused his offer.neednt have done 表示做了本来不必去做的事 注意：didnt need to do表示“没必要做而实际上也没有做某事”

6、You neednt have watered the plants, for it is going to rain.I didnt need to buy the dictionary. I had a copy at home.had better have done用于事后的建议，含轻微责备的口吻，意为“当时最好做了某事”，其否定式had better not have done表示相反的含义You had better have started earlier.You had better not have scolded her.would rather have done表示“当

7、时宁愿做了某事”，其否定式would rather not have done表示相反的含义，两者都表示“后悔”之意I would rather have taken his advice.I would rather not have told him the truth.was(were) to have done sth 过去未曾实现的计划或愿望The meeting was to have been held at 10 yesterday morning. He was to have attended the conference, but he fell ill. 专心-专注-专业