2.本能做而未做(表虚拟) should/ought to have done 本该做而未做 may/might have done 1.过去也许做了(表推测) 2.本可能做而未做(表虚拟) must have done 一定已经做了 needn't have done 本不必做而做了 　　From what you said, she must have told you all about it.

　　从你所说的来看，她一定把一切都告诉你了。

　　You should have told me earlier or I might have gone with them.

　　你本应该早点告诉我，不然的话我就会和他们一块去了。

　　They could have sent up the satellite successfully.

　　他们本来有能力成功发射这颗卫星的。

　　You ought to/should have been more careful.

　　你本应该更小心一些的。

　　You needn't have told them about it.

　　你本来没有必要告诉他们那件事。

　　[即时演练4]　用"情态动词＋have done"补全句子

　　①They must_have_been to the Great Wall, haven't they?

　　他们一定去过长城，不是吗？

　　②He can't/couldn't_have_watched TV last night, for he knew he would have a test.

　　昨天晚上他不可能看电视，因为他知道就要考试了。

　　③He could_have_passed the exam, but he was too careless.

　　本来他能够通过考试，但是他太粗心了。

　　④You should/ought_to_have_done more exercise before.

　　以前你本应该多进行锻炼的。

　　⑤You might/may_have_read about it in the newspapers.

　　你可能已经在报纸上看过这个消息了。

　　⑥I needn't_have_cooked so much food.Nobody was hungry.

　　我本不必做这么多吃的，大家都不饿。

　　Ⅰ.用情态动词和所给动词的正确形式填空

　　1．You ought_to/should_have_given (give) him some advice.He was too upset at that time.

2．You mustn't_smoke (smoke) in this part of the hospital.