语法系列之一 情态动词 编后

语法系列之一情态动词

一．基本用法

1. can ，could

1）表示能力“能”。如：He can speak English

2）表示推测，强调客观的可能性，“可能，会”，多用于疑问句，否定句。

表示推测时，情态动词后可用进行时，完成时。

如: Who can he be ?

She can’t be waiting for you.

He can’t have gone there alone.

3) 表示请求和允许，could语气更委婉。

如：Could you wait a few days for the money?

-- Can I go now? -- yes , you can.

4) 表示惊异，怀疑，不相信的态度。（用于否定句，疑问句，感叹句中）

如：Can this news be true ?

He can’t be our headmaster.

How can you be so foolish!

5)表示一时的情况，只用于肯定句，“有时会。。。”

如：Training by yourself in a gym can be highly dangerous.

She can be very forgetful.

2. may, might

1)表示允许，许可。

如：-- May I watch TV after supper ？

-- Yes，you may./ certainly / of course

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

-- May I smoke here ? -- yes, please / Please don’t

2)表示请求，允许，might 更加委婉。

如：--Might I use your telephone? -- Yes, please.

3)表示可能性的推测，“或许, 大概，可能”，用might 语气更加不肯定。

如：It may be true. He might have some fever.

4)用于祈使句表示祝愿。

如：May you succeed! 祝你成功！

May that day come soon! 希望这一天早日到来！

May you be happy, healthy and wealthy! 祝你快乐，健康，富有!

5)may ( just ) as well, might as well 是固定表达，“不妨，还是。。。的好”

如：I needn’t wait; I may as well tell you now.

Since it’s a fine day, we might as well walk.

6)may/ may not / might be doing 表示猜测，“可能正在，可能不在

干。。。”

如：She may not be doing such silly things.

He may be doing his work.

3. must , have to

1)must 表示必须要做的事“必须”，否定mustn’t “禁止，不应该’’. must

引起的一般疑问句，肯定回答用must，否定回答用needn’t或don’t

have to.

如：-- Must I go now ?

-- No, you needn’t/ don’t have to（Yes, you must）

2) 表示推测“一定，想必”，只用于肯定句中。

如：You must be hungry after a long work.

3) 表示“偏偏，硬要，偏要”, 指做令人不愉快的事。

如：The car must break down just when we were about to start off.

4) must 强调主观想法，have to 强调客观需要。

4. shall

1)用于第一三人称疑问句中，表示说话人征求对方的意见和向对方请示。

如：Shall we begin our lesson?

Shall the driver wait ?

Shall he come in or wait outside?

2)用于二三人称陈述句中，表示说话人命令，警告，允诺，威胁等。

如：You shall go with me. （命令）

You shall have the book when I finish it . （允诺）

He shall be punished. （威胁）

5. should

1)表示劝告，建议“应该”. 如：You should keep your promise.

2)表示推测，“可能，按理应该”如：They should have arrived by two

c’clock.

3)用于委婉，谦逊地提出意见或建议。

如：I should think you are right.

I should advise you not to do that .

4)用于某些从句中表示虚拟语气。

a.用于表示建议，要求，命令的动词后的宾语从句中（动词有：

suggest, advise, order , demand, require, request, desire , ask ,

insist ）如：

He suggested that I (should) do the job用于suggestion, wish ,

requirement , order, advice, demand 等表示建议，

要求，命令的名词后的表语从句中或同位语从句中。如：

My suggestion is that you (should) do it at once.

b.用于下列主语从句中：

It is demanded / ordered / suggested / necessary / important …

that sb (should) do……如：

It is demanded that we(should)get everything ready by the end of

the week.

It is important that we (should) learn English well.

c.用于It is + adj / n. + that 从句中，表示惊奇，怀疑，不满等情绪。

should 可以省略.如：

It is a pity that you （should ）leave tomorrow.

It is strange that he should have said that.

d.用于why / how 引起的句中，表示说话人对某事不理解，感到意

外，惊异，“竟会”。如：Why should you be so late today ?

I don’t know why you should think that I did it.