can 的用法及练习

情态动词、can 的用法:

一、简介

1、结构:can + 动词原形,没有人称与数的变化。

2、否定形式:cannot/can’ t, cannot比缩略形式can’ t要正式。口语中一般用缩略形式。

例如:I can swim、

Daming can ride a bike、He can’t drive a car、

二、用法

1、表示能力(体力、知识、技能等),此时可用be able to代替。

例如:Mary can speak three languages、玛丽会说三种语言。

= Mary is able to speak three languages、

注意:(1)can只有一般现在时与一般过去式;而be able to则有更多的时态。

例如:I’ll not be able to come this afternoon、今天下午我将会来。

(2)当表示“经过努力才得以做成功某事”时应用be able to,不能用can。

例如:He was able to go to the party yesterday evening in spite of the heavy rain、

尽管很大雨,她昨天能来参加聚会。

2、表示请求与允许。

例如:---Can I go now?

--- Yes, you can、/ No, you cannot/can’t、

此时可与may互换。在疑问句中还可用could, might(不可用于肯定句、否定句或答语)代替,不就是过去式,只就是语气更委婉。

例如:--- Could I come to see you tomorrow?

--- Yes, you can、( No, I’m afr aid not、)

3、表示可能性猜测。

例如:The man over there can´t be my uncle、My uncle has gone to Beijing、

那个人不可能就是我的叔叔。我的叔叔去北京了。

三、练习题

( )1.---Susan’s parents have bought a large house with a swimming pool、

---It ______ be very expensive、

A.must

B.can

C.mustn’t D、can’t

( )2.The notebook______ belong to Sarah.Her name is on the cover.

A.might

B.can’t

C.must

D.mustn’t

( )3、--- May I put my bike here?

--- No,you______.You should put it over there.

A.cou ldn’t

B.needn’t

C.mustn’t

D.won’t

( )4.Boys,you______ be sitting in this room.It is for your teachers only.

A.shouldn’t

B.don’t have to

C.won’t

D.needn’t

( )5.---Whose pizza is this?

---I think it______ be mine.I’m the only one who ordered a pizza.

A.must

B.could

C.might

D.can’t

( ) 6、My brother can’t sing but he ______ play the piano、

A、can’t

B、doesn’t

C、can

D、don’t

( )7、You look tired、You ______ to have a good rest、

A、must

B、may

C、should

D、need

( ) 8、--- Why do you think the man is running ?

---He ______ be ______ for exercise because he is wearing a suit 、

A、must , running

B、can’t ; run

C、can’t ; running

D、could ; running

( )9、---Mum , I’ve been studying English since 8 o’clock、______ I go out and play with Tom for a while?

---No, I’m afraid not、Besides, it’s raining outside now、

A、Can’t

B、Wouldn’t

C、May not

D、Won’t