Question

should have done;must have done;need have done;could have done的区别是什么？

Answer 1

1.本应该做（却没做） 2.一定做了··· 3.本需要做 4.本能够做（却没做）

Answer 2

应该做而没有做
必须做而没有做
需要做而没有做
可以做而没有做

Answer 3

1.应该要做
2.必须要做
3.需要去做
4.可以去做

Answer 4

一、 “must+have+done”表示对过去事情的肯定推测，译成“一定做过某事”，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”表示对过去事情的否定推测，译成“不可能做过某事”。

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 can't have stolen your money. She has gone home. 玛丽不可能偷你的钱，她回家去了。

三、 “can+have+done”表示对过去行为的怀疑，用于疑问句，译成“可能做过……吗？”。

1. There is no light in the room. Can they have gone out? 屋里没有灯，他们可能出去了吗？

2. There is nowhere to find them. Where can they have gone? 到处找不到他们，他们可能到什么地方去呢？

四、 “could+have+done”是虚拟语气，表示对过去事情的假设，意思是本来能够做某事而没有做。

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。

五、 “may+have+done”表示对发生过的事情的推测，意思是“可能已经”或“也许已经”，用于肯定句中。

—What has happened to George?

—I don't know. He may have got lost.

—乔治发生了什么事？

——我不知道，他可能迷路了。

六、 “might+have+done”表示对过去事情的推测，might与may意思相同，但可能性更小。多用于虚拟语气结构中。

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。

七、 “would+have+done”虚拟语气，表示对过去事情的假设，意思是“本来会做”。

1. I would have told you all about the boy's story, but you didn't 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 wouldn't have achieved so much. 没有你的帮助，我是不会取得如此大的成绩。

八、 “should+have+done”意思是“本来应该做某事，而实际没做。” “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 shouldn't have been so harsh on him. 看，汤姆哭了，我本来不应该对他如此严厉。
十、 “need+have+done”表示本来需要做某事而没有做。“needn't+have+done”则表示“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。