专题05 情态动词can could may和感叹句-
知识点讲解
情态动词: 情态动词本身有一定的含义,但不能单独作为句子的谓语,必须后面紧跟动词原形(ought/have除外). 情态动词不能表示正在发生或已经发生的事情,只表示期待或估计某事的发生;情态动词没有人称、数和时态的变化(have除外).
一、can/could
can 可表示能力、允许、可能性、怀疑猜测,意为“能,会,可以”;can't意为“不会,不能,不可以”,还有“不可能”之意。could为can的过去式,用法与can类似,常用于过去时中;could还可用于现在时中表示委婉客气,相当于can;could也可表示惊讶怀疑,不相信,如:He couldn't be a thief.
●●●用法:
1、表示能力。
◆◆◆can 和could可以用来谈论主语所具备的能力,意为“能,会”。can表示主语现在所具备的能力;could表示主语过去所具备的能力。如:
(1)Millie can play the piano. 米莉会弹钢琴。
(2)I could speak English at the age of six. 我六岁的时候就会说英语了。
★★★注意:浅析can/could和be able to的区别:
1、)can只用于现在式,could只用于过去式,be able to可用于各种时态。
He can write well.=He is able to write well. Could you use a computer last year
They will soon be able to talk in English. We have not been able to finish the task om time yet.
2、)将来时:can没有将来式,此时要用will be able to。如:I will be able to speak English in three years.
但决定将来是否有能力时,也常用can。如:Can you come to see us next Sunday
3、)过去时:could表示一般能力,was/were able to表示具体场合的能力。如:
My father could speak English. He was able to translate this story into French. How many eggs were you able to get
could的否定式也可表示具体场合的能力。The question was so difficult that he wasn’t able to/couldn’t answer it.
4、)was/were able to表示过去一次性设法做成某事,成功地做了某事。不能用could。反意词:fail to do sth.
The man was able to run away.=The man managed to run away. =The man succeeded in running away.
5、)can后边可跟被动语态的不定式,但be able to后不能接被动语态的不定式。如:
The star cannot be see. (正)
The star is not able to be seen. (误)
2、表示允许、许可(常用于疑问句)。
You can go now.
3、有礼貌地提出“请求”。
Can/Could I have a look at your new pen 我可以看一看你的新钢笔吗?
注意:could不表示时态,只是提出委婉的请求,语气比can更加客气委婉。
4、表示可能性(理论上或是逻辑判断上)。
He can’t (couldn’t) have enough money for a new car. 他不可能有足够的钱买新车。
5、表惊异、怀疑、不相信、猜测等态度。主要用于否定句、疑问句或感叹句中。
How can you be so careless 你怎么这么粗心?
▲▲▲句式转换:
※1、肯定句:
主 + can/could + 动词原形 … 如:
※2、否定句:
主 + can’t/couldn’t + 动词原形 …
◆ can否定形式为cannot或can’t。 could否定形式为could not或couldn’t.
(1)She cannot/can’t swim.
(2)I couldn’t find my keys this morning.
※3、疑问句:
Can/Could + 主 + 动词原形 … 肯定回答: Yes, 主 + can/could(表过去的能力时用). 否定回答: No, 主 + can’t/couldn’t(表过去的能力时用). 如:
---Can you drive ---Yes, I can. / No, I can’t.
二、may/might
may表示允许、也许,意为“可以,也许,可能”。might是may的过去式,与may用法类似,常用于过去时中;用在疑问句中,还可表示委婉客气。
●●●用法:
1、)表示请求、许可,比can正式。如:May I watch TV this evening May I borrow your bike
2、)表示推测,谈论可能性,意为“可能,或许”,一般用于肯定句中。如:It may rain tomorrow.
3、)may的过去式为might,表示推测时可能性低于may。如: He might be at home. He is away from school. He might be sick.
4、)may 放在句首,表示希望、祈求、祝愿,常可译为“祝愿”。通常是用May+主+V结构。如:May you have a good time!May God bless you!
5、)固定短语(成语): may/might as well,后面接不带to 的不定式,意为"不妨"。如:If that is the case, we may as well try.
典型例题
Peter ___come with us tonight, but he isn't very sure yet. A. must B. may C. can D. will
答案B. 表可能性只能用may. 此句意可从后半句推出。
▲▲▲句式转换:
※1、肯定句:
主 + may + 动词原形 … 如:It may be about three o’clock.现在大概三点钟。
※2、否定句:
主 + may not/mustn’t/can’t + 动词原形 … 如:It may not take too much time to finish the homework.完成作业也许花费不了太多时间。
※3、疑问句:
May + 主 + 动词原形 … 肯定回答: Yes, 主 + may/can. 否定回答: No, 主 + mustn’t/can’t/may not. 如:
---May I watch TV after supper ---Yes, you may. 好的,你可以。 / No,you mustn’t.不,你不可以。
对may的一般问句的回答,肯定回答一般是:Yes, please./Certainly./ Sure等,否定回答一般是:Please don't./No,you can't/mustn't.
◆◆◆三、can和may表示“可能性”的区别。
can和may都表示“可能性”。如:He may be right. 他可能对。may be (可能是)He can’t be right. 他不可能对。can’t be (一定不是)
二者的区别如下:
1、)句子类型不同:一般说来,can多用于疑问句和否定句,表示怀疑或不相信等态度;而may则多用于陈述句(肯定),表示一种揣测。如:
Can it be true No, it can not be true.
Where can they be now
I hear there may be a few copies left.
What he said may not be right.
2、)二者所强调的意思不同:一般来说,can强调客观上的可能性,而may则强调主观上的推测或判断。如:
Man cannot live without air or water.
She may be in the library, I suppose.
She may not be there today.
3、)二者表示的语气不同:在否定句中,can表达的否定语气较强,意为“不可能”;而may表达的否定语气较弱,意为“可能不”或“也许不”。如:
That cannot be true. (=It is impossible that that is true.)
That may not be true. (=It is possible that that is not true.)
根据以上分析,我们可以归纳为三条原则:
(1) 在肯定句中用may不用can;
(2) 在疑问句中用can不用may;
(3) 在否定句中,若语气肯定,表示“不可能”时用can not,若语气不肯定,表示“可能不”时用may not.
◆◆◆can, could和may都可表示“许可”。其中,could语气更委婉,比can听起来更有礼貌。may则用在比较正式的场合。
(1)你能给我递一下那些书吗?Can you pass me the books
(2)请问,你能帮我吗? Could you help me, please
(3)王老师,我可以进来吗? May I come in, Mr Wang
(4) —我能骑一下你的自行车吗? —是的,你可以。给你。— Can I use your bike, John — Yes, you can. Here you are.
(5) —能不能请你洗一下餐具? —很抱歉我不能,我必须得做我的作业。
— Could you please do the dishes — Sorry, I can’t. I have to do my homework.
(6) —我能用一下你电脑吗? —当然可以了。 — May I use your computer — Of course you may.
◆◆◆can/could/may表示委婉语气(意为“可以,能”)
(1) can用于同学,同辈之间请求。
(2)could用于向长辈,老师,陌生人有礼貌的请求。
(3)may在正式场合,很有礼貌。
(4)can't 否定的回答 “不可以”。
例题精炼
一、单项选择
1.Lucy is good at basketball. She ________ play basketball very well.
A.can B.can’t C.must D.have to
2.—Can we talk about the books in the library
—________. We have to be quiet.
A.Yes, we do B.No, we don’t C.No. we can’t D.Yes, we can
3.—_____ I borrow your notebook, Judy
—Sure! I can lend it to you.
A.Can B.Need C.Must D.Should
4.I hope all my friends ________ to my birthday party this Saturday.
A.can come B.comes C.to come D.coming
5.I ________ swim when I was 10 years old.
A.can B.am able to C.could D.were able to
6.—Could you please tell me your number
—________.
A.Yes, please B.No, thanks
C.Yes, I could D.No problem
7.— I wonder if these are Jim’s glasses.
— They ________ be his. He doesn’t wear glasses.
A.could B.must C.can’t
8.—Mum, ________ I go out to play
—Sure.
A.does B.do C.am D.may
9.—Why hasn’t Tom come here
—I’m not sure. He ________ ill at home.
A.maybe B.may be C.was D.can’t be
10.The word “________” means “Sorry, please say it again”.
A.what B.sure C.would D.pardon
二、完成句子
11.欢迎来到江门。
Jiangmen.
12.我的汉语讲得不是很好。
I Chinese very well.
13.I can ride a horse. (改为一般疑问句并作肯定和否定回答)
a horse
Yes, .
No, .
14.——我现在可以回家了吗?——不,你不可以。
—May I go home now
—No, you .
15.他不可能在房间里。
He be in the room.
16.六岁之前,她就既会唱歌也会弹钢琴。
Before she was six, she .
17.我能看看您的照片吗
I a look at your photos
18.This red handbag must belong to Caral. (对划线部分提问)
this red handbag belong to
19.here, may, I, take photos
20.他们可能会在周末完成这项工作。
They finish the work at the weekend.
三、单词拼写
21.— you make a model plane
—Yes, I can.
22.—Could I use your English textbook
—Yes, you . Here you are.
23.That man (不可能) be Mr. Zhang. He has gone to Beijing on business.
24.I (能,会) fly a kite at the age of five.
25.—My phone doesn’t work. I use yours
—Sure. Here you are.
26.She could be (shop) in the supermarket.
27.—Where is Daniel, Jim
—He (也许) be in the reading room.
28. (好吧)!
29.—Don’t run in the hallway!
—S . I won’t do that again.
30.O ! My finger is hurt.
31. (喂), this is Mrs Smith speaking.
32.We should say “P ” if we don’t hear the questions our teachers ask clearly.
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参考答案:
1.A
2.C
3.A
4.A
5.C
6.D
7.C
8.D
9.B
10.D
11. Welcome to
12. can’t speak
13. Can you ride I can I can’t
14.mustn’t/can’t
15.can’t
16.could not only sing but also play the piano
17. Could/Can take/have
18. Who/Whom can/could
19.May I take photos here
20.might/may
21.Can
22.can
23.can’t
24.could/was able to
25.May/Could
26.shopping
27.may
28. All right
29.(S)orry
30.(O)uch
31.Hi/Hello
32.(P)ardon
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