高中情态动词用法总结

情态动词的用法

A. can; could; be able to

Can 1. 表示“能力”(此时过去时是could)

2.表示许可、请求，“可以”。--Can/Could I go now?

3 表示推测, 把握很大,could也可表推测,把握比can小。

--Look! Someone is coming! Who can it be?

--It can’t be him. He has gone to Paris.（不可能）/ He could be here soon. 他很快就来。

4 表示感情（惊异/不耐烦）“究竟，到底”（主要用于否定句，疑问句和感叹句中。）

How can you be so foolish?

What can it possibly be? 到底那是怎么一回事?

They can’t be working at this time of day.

5 肯定句中客观存在的可能性。“有时会，偶尔”

It can be quite windy there, especially in spring.

Could 1.表示能力，can 的过去式，过去能够

Could you speak English then? 那时候你会说英语吗?

2. 请求允许（委婉语气）（问句的答语不用could，而用can，）

Could [Can] I use your pen? ” “Yes, of course you can.”/ No, I’m afraid not.

3. 表示推测可能性（肯，否，疑）

We could go there this summer. 今年夏天我们可能要去那儿。(将来可能性)

You could be right, but I don’t think you are. 你可能是对的，但我并不认为你是对的。

4. could have done ①对过去推测，可能已经。。。②本来能够却没做，差点就

He can’t [couldn’t] have seen her there. 他不可能在那儿见到她。

He could have gone home. 他可能已回家了

He could have told her, but he didn’t choose to. 他本来可以告诉她的，但他却没有。

B. may 和might

1.表示允许﹑许可，might提问更委婉。

---May/Might I watch TV after supper?

---Yes, you may./ Yes, please./ Certainly.

---No, you mustn't. / No, you may not. / No, you can’t./No, you’d better not.

2. 表示推测，有“或许”、“可能”的意思。might把握更小。疑问句用can/ could.

•He may/might be right./ I hear there may be a few copies left.

•He may/might come today (tomorrow).

3. may表示祝愿，倒装。May +主语+动词原形。May you succeed!/May you all be happy. ☆may [might] as well…意为“不妨”、“还是…为好”等，用might 比用may 语气更委婉。如：I’m ready，so I might as well go now．我已准备好，因此不妨现在就走。

There’s nothi ng to do, so I may [might] as well go to bed.

☆may well... 完全可能

C. must, have to

Must 1. 表示“必须”。否定式mustn’t表示“不可以”、“不准”、“禁止”等。

Everybody must obey the rules../You mustn’t lend it to others./You mustn’t speak like that to your mother.

☆在回答有“must” 的询问时，--- Must I go now? --- Yes, you must.

---No, you needn’t. / No, you don’t have to.

2. must表示推测（“一定”、“必定”），表肯定的推测, 其否定的推测用can’t，表示“不可能”。You must be hungry after the long walk. / It can't be Jim, for he has gone to Beijing.

The Chinese language must have the large number of speakers.

3．must 表示说话人不耐烦的态度，“干嘛偏要”

☆must + have + done，表示对过去事物的肯定推测。“一定做过...”

He must have told my parents about it. 他一定把这件事情告诉我父母亲了。

☆must表示推测时，其反意疑问句应根据动词的实际时态而变化。如：▪It must be nice to take a walk here, isn’t it?

▪Tom buys a lot of apples ,he must like eating them, doesn't he？

Must have done 的反意疑问句有三种情况:

①从句中含有过去的时间状语,反意疑问句用过去时.

▪The ground is wet , it must have rained last night, didn’t it?

②从句中含有过去完成时的时间状语,反意疑问句用过去完成时.

▪By the end of last term, we must have learnt 2000 words, hadn’t we?

③若从句中不含任何时间状语,反意疑问句用现在完成时

▪We must have been met somewhere (before), haven’t we?

☆must 表示“必须”“有必要”时，反义疑问句部分用mustn’t...? 或needn’t ...?

You must go home right now, needn’t you?

☆must 用否定形式mustn’t时，附加疑问句部分用may或must…?

You mustn’t cheat in the examination, must you?

3. 表示与说话人愿望相反及不耐烦．意为“偏要”．

-____you make so much noise?

-Sorry, I will take care not to. A Must B Can C May D Would

4. must 和have to 的区别:

D. ought to/ should/ shall

Ought to ought to用于反映客观情况或涉及义务和规定时，常译作“应该”、“应当”(和should差不多，只是语气较强)，有时表示非常可能的事情。

•There ought not to be much noise in a hospital.

•--- Ought he to go? --- Yes, he ought to.

•If she is completely well, she ought to be back at school today.

ought to have done指过去动作,表示一件事情该做而未做。

ought not to have done 表示一件不该做的事情却做了。

should 1.用于表示劝告和建议，“应该”．表示自己的主观看法,语气比ought to弱。

☆should + have done 指过去动作,表示一件事情该做而未做。

should not + have done 表示一件不该做的事情却做了。

--- Who did it sound like? Anybody you know?

--- Well, perhaps Jeff. I should have asked who was calling before he hung it up.

2.表推测，“按道理，按常理应该”

They should have arrived by two o’ clock.

3.表示惊讶,赞叹，不满，责备“竟然”

I am sorry that you should do such a thing.

4. 用于if引导的虚拟条件句中，表示一件事听起来可能性小，但也不是完全不可能。有“万一”的意思

Should I be free tomorrow, I’ll come.