英语的几道语法问题求解

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.