高考英语一轮复习——情态动词完成时态的用法 教案

“情态动词+have done”用法归纳  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”①She must have gone through a lot.②He must have visited the White House during his stay in the United States.may have donemight have done① 表示对过去已发生行为的推测，意为“也许/或许已经（没有）……”② 一般用于肯定句或否定句中，不用于疑问句③ 用might则表示语气更加不肯定①You may have learnt the news.②He may not have heard his name called.③Sorry I’m late. I might have turned off the alarm clock and gone back to sleep again.might have done① 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② 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  ①You should not swim in that sea; you might have been eaten by a shark.② He might have given him more help, thought he was busy.can…have donecannot have done① 只用在否定句和疑问句中①       表示对过去发生的行为的怀疑和不肯定③ can换成could时语气委婉① Where can she have gone?② Could he have done such a foolish thing?③ The boy can’t have finished reading the book so soon because it is difficult even to an adult.could have done① 可用在肯定句、否定句和疑问句中② 表示“可能已经……”② 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① He could have killed himself driving at a dangerous speed.②You could have been more considerate.③You could have done better, but you were too careless.should/ought to have done① 用于肯定句时，表示本该做某事，而实际上未做② 用于否定句时，则表示不该做的事反而做了①He should have known that the police would never allow this sort of thing.②You shouldn’t have done it so carelessly.③You ought to have returned the book earlier.④You ought not to have refused his offer.needn’t have done① 表示做了本来不必去做的事② 注意：didn’t need to do表示“没必要做而实际上也没有做某事”①You needn’t have watered the plants, for it is going to rain.②I didn’t 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①You had better have started earlier.②You had better not have scolded her.would rather have done表示“当时宁愿做了某事”，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①I would rather have taken his advice.②I 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①The meeting was to have been held at 10 yesterday morning. ②He was to have attended the conference, but he fell ill.