1) may(might) have + done sth, can (could) have + done sth 表示過(guò)去，推測(cè)過(guò)去時(shí)間里可能發(fā)生的事情?！ hilip may (might) have been hurt seriously in the car accident. Philip can (could) have been hurt seriously in the car accident. 2) must have +done sth，對(duì)過(guò)去時(shí)間里可能發(fā)生的事情的推測(cè)，語(yǔ)氣較強(qiáng)，具有"肯定"，"諒必"的意思?！?--Linda has gone to work, but her bicycle is still here. ---She must have gone by bus. 3) ought to have done sth, should have done sth 本應(yīng)該做某事，而事實(shí)上并沒(méi)有做。否定句表示"不該做某事而做了"?！ ou ought to (should) have been more careful in this experiment. He ought not to have thrown the old clothes away.（事實(shí)上已扔了。） ought to 在語(yǔ)氣上比should 要強(qiáng)。 4) needn't have done sth 本沒(méi)必要做某事 I dressed very warmly for the trip, but I needn't have done so. The weather was hot. 5) would like to have done sth 本打算做某事 I would like to have read the article, but I was very busy then.