1. 情态动词+ have + done

(1)must have +done sth.对过去时间里可能发生的事情的推测，语气较强，表示＂肯定已经……＂。

☛Since the road is wet, it must have rained last night.

因为路是湿的，所以昨晚肯定下雨了。

(2)can’t have done 表示＂不可能已经……＂。

☛He can’t have lost his way. I drew him a map.

他不可能迷路了。我给他画了地图。

(3)could / may / might have done推测过去某事＂也许＂发生了；也可表示虚拟，意为＂本可能，本能够＂。

☛I can’t find my keys. I may / might have left them at the school yesterday.

我找不到钥匙了。可能昨天我把它们落在学校了。

☛You could have told us earlier.

你本可以早点告诉我们的。

(4)ought to / should have done 表示＂本应该……＂；否定形式ought not to / shouldn’t have done 表示＂本不应该……＂。

☛With all the work finished, I should have gone to the party last night.

完成了所有的工作，我昨天晚上本应该去参加聚会的。

☛You ought not to have made fun of him. He is not the one you laugh at but learn from.

你本不应该取笑他的。你不应该取笑他，而应该向他学习。

(5)needn’t have done/not have to do表示＂本没必要……＂。

☛You needn’t have waken me up.

你本没有必要叫醒我的。

☛I don’t have to go to work today.

我今天没必要去工作。

(6)would like /love to have done sth.表示＂本打算/本想……＂。

☛I would like to have read the article, but I was very busy then.

我本打算读这篇文章的，但是当时我太忙了。

2. 情态动词+ be + doing

情态动词+ be + doing表示推测或评论某动作现在是否正在进行。

☛He must be playing basketball in the room.

他肯定正在房间里打篮球。

☛She may be staying at home.

她肯定正待在家里。

【特别提醒】

陈述部分有must的疑问句，疑问部分根据实际情况而定。

☛You must have studied English for three years, haven’t you?/didn’t you?

你肯定学过三年英语，是吗？

☛He must have finished it yesterday, didn’t he?

他昨天一定做完了，是吗？