情态动词can的基本用法.doc

情态动词can的基本用法：
情态动词can有一定的词义,但不能独立存在,它必须与动词原形一起构成谓语。情态动词can没有人称和数的变化。其具体用法如下:
1.表示"能、会",指脑力或体力方面的"能力"。例如:
I can speak English.我会讲英语。
Jim can swim but I can't.吉姆会游泳,但我不会。
2.表示"可能",常用于否定句或疑问句中,指某种可能性，此时can’t 译为“ 不可能”。例如:
Han Mei can't be in the classroom.韩梅不可能在教室里。
Can he come here today, please?请问他今天能到这里来吗?
3.表示"可以",常用于口语中,指许可或请求做某事，可以代替may。例如:
Can I have a cup of tea, please?请问我可以喝一杯茶吗?
You can go out.你可以出去了。
补充：can的过去式could，意为“ 能、 会”，表示过去的能力
如：He could write poems when he was 10.  他十岁时就会写诗。
could在疑问句中，表示委婉的语气，此时 could 没有过去式的意思。如:Could you do me a favour? 你能帮我个忙吗？—Could I use your pen? 我能用一下你的钢笔吗? —Yes, you can.可以。（注意回答）

情态动词can的基本句型：
1.肯定句型为:主语+can+动词原形+其它。例如:
They can play basketball.他们能打篮球。
She can dance.她会跳舞。
You can go to watch TV.你可以去看电视了。

2.否定句型为:主语+can not(can't/cannot)+动词原形+其它。表示"某人不能(不会。不可能)做……"。其中can't是can not的缩略式,英国多写成cannot。例如:
You cannot pass the ball like this.你不能像这样传球。
I can't ride a motorbike.我不会骑摩托车。

3.疑问句句型分为:一般疑问句句型和特殊疑问句句型两种类型。
⑴一般疑问句句型为:Can+主语+动词原形+其它。表示"某人会(能。可以)做……吗?",用于口语时,常表示请求或许可。其肯定答语用""Yes,主语+can."作答;否定答语用"No,主语+can't."作答。注意答语中做主语的人称代词,应根据问句中的主语作相应的变化。其变化规则为:第一人称问,则第二人称答;第二人称问,则第一人称答;第三人称问,第三人称答。例如:
①-Can you sing an English song for us?你可以为我们大家唱一首英语歌吗?
-Yes.行。(注意在Yes后面常省略I can)
②-Can I skate?我可以滑冰吗?
-Yes, you can.可以。
③-Can she climb hills?她能爬山吗?
-No, she can't.不,她不能。
⑵特殊疑问句句型为:
a. Who+can+动词原形+其它。该句型中who相当于主语。例如:
-Who can sing in English in your class?你们班上谁会用英语唱歌?
-Lily can. 莉莉会。
b.特殊疑问词(作定语)+名词+can+主语+动词原形+其它。该句型中的特殊疑问词常用how many, how much等。例如:
-How many boats can you see in the river?你能看见河中有多少只船吗?
-Only one boat.仅有一只。
c.特殊疑问词+can+主语+动词原形+其它。该句型中的特殊疑问词常用what, where, when等,一般用肯定陈述句作答。例如:
-What can you see in the picture?你能在图画中看到什么?
-I can see some birds and two big trees in it.我能看到一些鸟儿和两棵大树。

考查can的用法：
a. 考查can表示能力的用法。
在这一用法中，can表示能力，意思是"能，会"，其否定式can't表示"不能"。在过去时中用could和couldn't。例如：
1. --- Where's Mr. Lee? I have something unusual to tell him.
--- You ________ find him.
A. may not B. may not C. can't D. can't
2. --- Finish drawing a horse in ten minutes. OK?
--- Sorry. It ________ in such a short time.
A. may do B. can't be done C. must do D. needn't be done
3. I have my own room in my house, so I ________ do what I want in it.
A. must B. have to C. need to D. can
4.________you mend my car? I ______ not start it.
A. Would; would B. Must; must C. Can; can D. May; may
5.________she ride when she was three years old?
A. Can B. Could C. Need D. May
6. The boy ________ answer this kind of hard questions one year ago.
A. can B. may C. could

b. 考查can表示推测的用法。
在这一用法中，can意为"可能"，表示客观可能性，常常用于疑问句和否定句中。例如：
7. --- Who is the man over there? Is it Mr. Li?
--- No, it ________ be him. Mr. Li is much taller.
A. mustn't B. may not C. can't D. needn't
8. --- Listen! Someone is singing in the next room. Who ________ it be? Is it Wei Fang?
--- No. It ________ be her. She is at school now.
A. will; may not B. must; mustn't C. may; can't D. may; won't
9. --- Is Mr. Hu in the reading room?
--- No, he ________ be there. He has gone to Tianjin.
A. mustn't B. needn't C. won't D. can't
10. Class 3 won the football match! ________it be true?
A. May B. Must C. Will D. Can

c. 考查can / could表示请求许可的用法
在这一用法中，can和could都表示现在，用could比用can语气更加委婉客气，常用Could I / you...?句式，表示"我/你能……吗?"，若表示同意要用can，不用could。例如：
11. --- Could I look at your pictures?
--- Yes, of course you________.
A. could B. can C. will D. might
12.________you pass me a pen? I'd like to write down the telephone number.
A. Need B. Could C. Must D. Should

综合练习：
1. ---Can I go fishing with you, Dad?
---No, you _____.You ______stay at home and do your homework first.
A. won't; may B. can't must C. shouldn't; ought D. needn't; should
2. ---Do you know whose dictionary it is?
---It ______ be Li Mei's. Her name isn’t on it.
A. can't B. mustn’t C. shouldn't D. needn't
3. ---I can't stop smoking, doctor.
---For your health, I'm afraid you ______.
A. can B. can't C. must D. mustn't
4. ---Is Mr. Brown driving here?
---I'm not sure. He ______ come by train.
A. may B. shall C. need D. must
5.— _____ your friend play basketball?
—No, he _____.
A. Cans; can’t B. Can; doesn’t
C. Does can; doesn’t can D. Can; can’t