情态动词的用法

高一必修三情态动词语法讲解及例句

情态动词的用法：

一． Can和 could 的用法

1．表示能力，如：

My mother can use the computer now .

When she was young ,she could dance very well.

2. 表示许可(多用于口语)

Can I go now?

He said I could use the computer .

3. 表示请求 ,Could I ……比can I…….客气委婉，但是回答均用can.

--Could I borrow your pen ?

---Yes ,you can .

4. 表示推测，意为 “可能”，多用于疑问和否定句中。表示理论上的可能时可用肯定句中。 Anybody can make mistakes.

Man can not live without air.

Who can be he?

She can’t be waiting for you.

5. can与be able to 的用法比较

①表示能力时二者同义

No one can/is able to do it.

②表示过去成功的做某事用was/were able to do ,不用could ..

With the help of the fireman they were able to leave the burning house.

The fire spread throuth the hotel very quickly but everyone was able

to get out in the end.

二． may和might的用法

1. 表示许可，有“可以”的意思，有时可以与can互换。

You may go now.

May I smoke in the room?

2. 表推测，有“或许、可能”的意思，只用在陈述句中

It may rain tomorrow.

He may come or may not.

3 might比may的口气委婉。might表示现实的可能性更小一些

He might come soon.

I wonder if I might have some coffee.

4 may的否定式

①may not 意为“不可以”，语气较客气，常用来回答May I…问句.

—May I go there?

—No, you may not.

② may not 意为“不可以，不许”，语气较强，有命令强制的意味，常用来回答Can I…问句.

—Can his words be trure ?