1 情态动词+have done 用法及练习 1. must have done 表示对过去或已经发生的行为或状态进行确有把握的推测， 意为“肯定做了某事 ”；只能用在陈述句的肯定句中。 It must have rained last night, for the road is wet. The lights were out. They must have been asleep. 2. can’t/couldn’t have done sth. 表示对过去或已经发生的行为或状态进行确有把的推 意为“不可能做了某事 ”；只能用在陈述句的否定句中。 He was with me last night. He can’t/ couldn’t have gone to the theatre. I saw Mr. Wang just now. He couldn’t have gone to Beijing. Can/Could … have done sth?表示对过去或已经发生的行为或状态的怀疑. 意为“可能已经…吗？”。用在疑问句中。 He didn’t attend his sister’s birthday party. Can/Could he have forgotten it? 3.could have done sth. 用于陈述句的肯定句中时是虚拟语气，表示没有实现的可能性， 意为“本来可以做，可能已经做”。有一种对过去为付诸实施的事情的惋惜。用于肯定句中 You could have done better, but you were too careless. 4.may/might（not）have done sth 表示对过去或已经发生的行为或状态进行推测 意为“可能(没有)做了某事 ；只能用在陈述句的肯定和否定句中。 It’s too late. I think he may have gone to bed. He might not have finished the work. 5.Should/ought to have done sth 表示“本应该做…”而实际上没做 Should/ought not to have done sth. 表示“本不应该做”而实际上做了 You should have come to the meeting earlier. You ought to have done this exercise . You shouldn’t have told her the truth. He ought not to have treated his parents like that. 6.needn’t have done sth. 表示做了“本来不必做的事 didn’t need to do 表示“没有必要做而实际上也没有做的事“ You needn’t have taken a taxi here, for it was very near to my house. I didn’t need to clean the windows. My brother did it. 7.had better have done sth. 用于事后的建议， 含轻微的责备的口吻， 意为“当时最好做了某事“， 其否定...
