英语的几道语法问题求解can/would/must/need +have done各个的用法

英语的几道语法问题求解can/would/must/need +have done各个的用法
英语的几道语法问题求解
can/would/must/need +have done
各个的用法

英语的几道语法问题求解can/would/must/need +have done各个的用法
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.

must，绝对肯定，could是can的过去分词形式，need理解成需要的意思，have done为一二人称现在完成时

它们都是modal verb
can:
Don't worry yourself about me, I can take care of myself...不用为我担心,我会照顾自己.
Exercising alone can be boring... 只是做运动是会很闷的.
Coral can be yellow, blue, or green. 珊瑚可以是黄...

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它们都是modal verb
can:
Don't worry yourself about me, I can take care of myself...不用为我担心,我会照顾自己.
Exercising alone can be boring... 只是做运动是会很闷的.
Coral can be yellow, blue, or green. 珊瑚可以是黄色,蓝色或绿色.
would:
No one believed he would actually kill himself... 没人相信他会自杀.
Would he always be like this?... 他经常都这样吗?
It would cost very much more for the four of us to go from Italy. 我们四个人从义大利去会花更多钱.
must:
The doctor must not allow the patient to be put at risk... 医生不能让病人有危险.
Equipment must be supervised if children are in the house. 有小孩在家,工具/机器要有人监视.
I must have been a bore. 我是很闷的一个人..
need + have done:
I need to rest for I have done so much work. 我需要休息因为我做了很多工作.
They need to apologise if they have done something wrong. 如果他们有做错,他们就要道歉.
没时间细解,希望对你有用.

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答：1. must have done用于对过去发生过的事进行肯定推测：
He must have done sth. (yesterday).
他（昨天）肯定做过某事。
2. would have done sth. 一般用于虚拟过去的主句：
If sth. had happened, sb. would have done sth.
如果当时发生了某事，...

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答：1. must have done用于对过去发生过的事进行肯定推测：
He must have done sth. (yesterday).
他（昨天）肯定做过某事。
2. would have done sth. 一般用于虚拟过去的主句：
If sth. had happened, sb. would have done sth.
如果当时发生了某事，某人就会已经做过某事了。
3. can have done sth. 常见的是could have done sth. 表示过去本来是能够做某事的。
更常见的是can't/ couldn't have done sth. 与must have done sth. 的用法相同，只是意思相反，表示过去不可能做过某事如：
He can't/couldn't have done sth.(yesterday).
他（昨天）不可能做过某件事。
4. need have done sth. 这个用很少见，应该是“本来需要做某事”的意思，但不太有实例支持。常见的是：
needn't have done sth. 表示“本不需要做某事”

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