英语语法最终珍藏版笔记-6“情态动词+have+ done”的含义

“情态动词+have+ done”的含义

1、Must have done的含义。“must have+过去分词”表示对过去的推测,意思是“一定已经,想必已经,准是已经….”,只用于肯定句中。例如:

The streets are wet. It must have rained. 街道是湿的,准是下雨了。 

He must have been drinking beer. 他肯定一直喝啤酒来着。

若要表示否定,要用“can’t/couldn’t+ have+过去分词”,意 思 是“不可能”:

The money can’t have been lost there. 钱不可能是在那儿丢的。

2、 May/might have done 的含义。“may/might have+过去分词”表示对过去的推测,意思是“也许已经┅,可能已经…”。用于肯定或否定句中。疑问句中用can或could. “might(不是may)have+过去分词”也表示“本来可以…”的意思,含有责备的口气,用来批评人。例如:

He may have gone to bed. 他可能已经上床睡觉了。

She might not have settled the problem. 她可能尚未解决那个问题。

You might have told me earlier. 你本可以早点告诉我的。(埋怨责备)

Don’t do that again. You might have been fired. 别那么干了,会把你解雇的。(责备,警告)

You might have succeeded if you had tried. 假如你尝试过,或许已经成功了。(虚拟语气,不满)

3、needn’t have done的含义。“needn’t+ have+过去分词”表示“作了不必做或不需要做的事”。 可译成“大可不必”,“本来不需要”。例如:

I needn’t have borrowed the money yesterday. 昨天我根本不需要借钱的。(实际上已经借了)

You needn’t have come so early. 你不必那么早来嘛。

4、can/could have done:用来谈过去的情况

1在疑问句、否定句中,表示怀疑和不可能,这时它们没有时间上的差别,只是could的语气更弱一些:

Who could have taken them? 谁会把它们拿走了呢?

Where can he have gone? 他可能到哪儿去了呢?

He can’t have taken it home. 他不可能是带回家去了。

She couldn’t have left so soon. 她不可能这么快就走了。

I don’t see how I could have done otherwise. 我看不出我当时还有别的做法。

Who could have supposed you were going to do such a thing? 谁会想到你会做出这样的事情。

Nobody could have foreseen such a calamity. 这样的灾祸谁也不会预想到。

2could have done(但不是can)在肯定句中,表示“那时本来可以…;差点就要…”,有时用来进行婉转地批评(与might同意,但语气更强一些):

We could have solved the problem in a more reasonable fashion. 这个问题我们本来是可以更合理得解决的。

He could have told her, but he did not choose to. 他本来可以告诉她的,但他不愿这样做。

When she heard the news, she could have cried. 听了这消息,她简直要哭出来了。

I could have died laughing. 我简直要笑死了。

You could have been more considerate. 你其实可以想的更周到一些。

We could have started a little earlier. 我们其实可以更早一些动身的。

The result could have been better. 结果本可以更好一些。

5should/ought to have done的含义。 “should/ought to have+过去分词”表示“过去应该做谋事却没有做”;“should not/ought not to have+过去分词”表示“做了不应该做的事”。含有责备或遗憾的意思。例如:

You shouldn’t /oughtn’t to have come here alone at such a late hour. 你这么晚的时候本不一该一个人来这里的。(实际是一个人来的)

She should/ought to have gone there alone. 她本该一个人去那里的。(实际上不是) 

You should have come here ten minutes earlier. 你本应该早10分钟来才是。

The boy shouldn’t have been playing the piano. 那孩子不应该一直在弹钢琴。

6、might, may, must表示推测时的区别: may,might, must可表示 推 测“可能”.根据表示可能性的大小,我们把这三个词排列为:might<may<must(或许→可能→肯定)。例如:

It might rain tomorrow.  (将来)明天可能下雨。

They might be watching TV now.  (现在)他们可能正在看电视。

Jane might have visited the Summer Palace last year.  (过去)去年珍妮可能去过颐和园。

He may have something important to do.  (现在)他可能有更重要的事要做。

They may have been to Shanghai last summer.  (过去)去年夏天他们可能去过上海。

There must be something wrong with him.  (现在)他肯定出问题了。

He must have made a mistake.  (过去)他一定是犯了个错误。

第四部分 几个用法的区别

1、 can 和be able to的区别。can在表示“能力”时与be able to同义。但是can的时态形式不如be able to多。在一般将来时和现在完成时中只能用be able to。如:

She will be able to dance in a week. 她再过一星期就会跳舞了。

Nobody has ever been able to do it. 从来没有人能够做这事。

在过去时中,could表示具备某种能力,但不一定做事;而was able to表示努力设法去做谋事,成功后说明有能力,相当managed to do或succeeded in doing。这时,could和was able to是不能互换的。例如:

When he was a boy, he could swim across the river in fifteen minutes. 他小时侯,15分钟就能游过那河。(could表示能力,但不一定这么做)

He was able to swim across the river in fifteen minutes last week.

=He managed to swim across the river in fifteen minutes last week.

=He succeeded in swimming across the river in fifteen minutes last week.

上周他15分钟就游过了那河。(was able to表示真这样做了,而且成功了。这里不能用could)

2must与 have to的比较。 Must 强调主观意志,也就是说,必要性来自说话者的主观意志。 have to 强调客观因素。例如:

He must stop smoking. 他必须戒烟。(说话人认为他必须)

This is an awful film. ?We really must go. 这部电影糟透了-我们一定要离开这里。(说话人认为必须)

You have to go and see the boss. 你一定得去见见老板。(客观因素)

Catholics have to go to church on Sundays. 天主教徒星期天必须去做礼拜。(客观因素,如教规等 )

注意:must not表示“绝对不可”; don’t  have to(或 haven’t got to )表示“不必,没必要”,两者意思极为不同。英国英语中常用needn’t来代替 haven’t got to 或don’t have to,如:

You mustn’t tell Jenny. =Don’t tell Jenny. 你一定不要告诉珍妮。

You don’t have to tell Jenny. =You can if you like but it isn’t necessary. 你不必非要告诉珍妮。

3need 作为情态动词与行为动词的区别。作为情态动词,need 无过去式和将来时,故用had to, will have to替代,主要用在否定句、疑问句、条件句中,意思是“有必要”。例如:

He need not come at once. 他不必马上就来。

If you need go there, please tell me now. 如果你需要去那儿,请告诉我。

Need he come at once? 他必须马上回来吗?

(回答要用must, have to, ought to, should等。例如:Need he come at once? Yes, he must/ought to /should/has to. No, he needn’t /doesn’t have to /mustn’t.)needn’t have done表示“本来不必做某事而实际上已经做了”。例如:

We needn’t have waited for him. 我们本来不必等他的。(实际上已等他了)

用作实义动词时,need可用于肯定句、 否定句和疑问句,是“需要”之意。如:

You need to wash your hands. 你需要洗手。

Does he need to take the medicine four times a day? 他需要每日服药四次吗?

We didn’t need to see him at all. 我们根本不必要看他(实际上也没去看他,请比较needn’t have done的用法)

need做实义动词时,后面的宾语如果是动名词,用主动形式表示被动意义,如果是不定式的被动形式,来表示被动意义。类似need的这种用法,还有require, want等。例如:

The dinning room needs cleaning every day. =The dinning room needs to be cleaned every day. 食堂需要天天打扫。

My shoes need repairing. = My shoes need to be repaired. 我的鞋需要修理。

4would与 used to 的区别 .would 可表示反复发生的动作或某种倾向。used to表示过去的习惯动作或状态,强调现在已不存在。例如:

She used to work into the night. 过去她常工作到深夜。(现在不了)

She would work into the might. 以前她常工作到深夜。(不表示现在不了)

People used to think that the sun went round the earth. 以前人们总认为太阳是围绕地球转的。(现在不这样认为了)

I used to smoke quite a lot, but I have given it up. 我过去抽烟很凶,现在戒了。

情态动词的重点和难点是:情态动词之间的区别;表示“推测”的表达方式;以及“情态动词+have+过去分词”的含义。