情态动词+havedone的用法课件.ppt

“情态动词+have done”的用法 　一、 “must have done” 一定做过某事 表示对过去事情的肯定推测，该结构只用于肯定句。 1. It must have rained last night, for the ground is wet. 昨晚一定下雨了，因为地面还是湿的。 　2. You must have been mad to speak to the servant. 你和仆人说话，一定是发疯了。 二、 “can’t have done” “couldn’t have done” 不可能做过某事 表示对过去事情的否定推测，“couldn’t have done”较少使用。 1. Mr. Smith can’t have gone to Beijing, for I saw him in the library just now. 史密斯先生不可能去北京了，我刚才还在图书馆见过他。 2. Mary cant have stolen your money. She has gone home. 玛丽不可能偷你的钱，她回家去了。 　三、 “could have done” 1)表示猜测，“过去可能做过某事”,多用于疑问句； 2)用于虚拟语气，意思是“本来能够做某事而没有做”。　 What could have happened? 难道可能发生了什么事吗？ This glass is cracked. Someone could have dropped it.这个玻璃杯破了。可能是谁把它掉在地上了。 　He 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。 “can… have done” 表示对发生过的事情的推测，用于疑问句中。 It`s so late. Where can she have gone? 天晚了，她可能去哪儿了呢？ 　五、 “might have done” 1)表示对过去事情的推测，might与may意思相同，但可能性更小。 2)用于虚拟语气中,意思是：“本来可能做某事，事实上却没做” 1. He might have given you more help, even though he was busy. 他或许会多给你一些帮助，即使他很忙。 2. She might have achieved greater progress, if you had given her more chances. 如果你多给她点机会，她可能已经取得更大的成绩。 六、 “would have done” 虚拟语气，意思是“本来会做某事，但事实上没做”。 1. I would have told you all about the boys story, but you didnt ask me. 我本来会告诉你这个小男孩的故事，但是你没有问我。 2. Without your help, I wouldnt have achieved so much. 没有你的帮助，我是不会取得如此大的成绩。 七、 “should have done”本来应该做某事，而实际没做 否定式为“shouldn’t have done”表示本来不应该做某事，而实际做了。含有指责对方或自责的含意。 1. Tom, you are too lazy. The work should have been finished yesterday. 汤姆，你太懒惰了，这项工作本来应该昨天就做完的。 2. Look, Tom is crying. I shouldnt have been so harsh on him. 看，汤姆哭了，我本来不应该对他如此严厉。 　八、 “ought to have done” 表示过去应该做而实际并没有做，译成“理应做……”，往往表示遗憾。与“should+have+done”用法基本一样。 　I ought to have gone home last Sunday. 我理应上星期日回家。 You ought not to have given him more help. 你不应该帮助他那么多。 十、 “need have done” 本来需要做某事而没有做 否定式为 “needn’t have done” 表示“本来不需要做某事而做了”。 I needn’t have bought so much wine—only five people came. 我本来没有必要买这么多酒，只来了五个人。 He need have hurr