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第七讲 初中英语情态动词讲解
一、 情态动词的概念
情态动词本身有具体的词义,但也同助动词一样,需要与其他词语一起构成句子的谓语。
情态动词有四个特征:
① 不能单独做谓语,必须与其他动词一起构成谓语;
② 没有人称和数的变化;
③ 情态动词后必须跟动词原形;
④ 具有助动词功能。
二、 情态动词的用法
1. can的用法:
1) 表示能力,译为“能、会”,即有某种能力,尤其是生来具备的能力,此时may和must不可代替它。
例句:She can swim fast, but I can’t . 她能游得很快,但我不能。
例句:I can see with my eyes. 我用眼睛看。
2) 表示许可,常在口语中。这里可以用may代替。
例句:You can/may use my dictionary. 你可以用我的字典。
3) 表示推测,意为“可能”,常用于否定句和疑问句中,此时can’t不是“不能”而是“不可能”。
例句:The news is true. 这消息是真的。
一般疑问句:→ Is the news true? 这消息是真的吗?
表推测、怀疑:→ Can the news be true? 这个消息会是真的吗?
例句:- Can it be our teacher? 那个人有可能是我们老师吗?
- No, it can’t be our teacher. He is visiting the Great Wall.
不可能。咱们老师正在游览长城呢。
【例题】—I think Miss Gao must be in the library. She said she would go there.
—No. She _____ be there, I have just been there.
A. can’t B. mustn’t C. needn’t D. wouldn’t
注意:can和be able to的区别
表达“能够”的时候,两者可以互换。但是细微的差别在于:
can 强调与生俱来的能力,“能够”;
be able to是后天习得的能力或者经过努力、拼搏、奋斗而做成的事,“有能力做”。
例句:They can/are able to be here on time.
他们能够及时赶到。
例句:They were able to arrive here on time with his help.
有了他的帮助,他们就能及时赶到这里了。
例句:They can arrive here on time.
他们能够及时赶到这里。
2. could的用法:
1) can的过去式,意为“能、会”,表示过去的能力。
例句:He could write poems when he was 10. 他十岁时就会写诗。
2) could在疑问句中,表示委婉的语气,此时could没有过去式的意思。
例句:Could you give me a hand? 你能帮我个忙吗?
例句:— Could I use your pen? 我能用一下你的钢笔吗?
— Yes, you can.可以。(注意回答是can能够)
3. may的用法:
1) 表示请求、许可,比can正式
例句:May I borrow your bike? 我可以借你的自行车吗?
例句:You may go home now. 现在你可以回家了。
【例题】— _______ I borrow your MP3?
— Sure . Here you are.
A. May B. Should C. Must D. Would
2) 表示推测,谈论可能性,意为“可能,或许”,一般用于肯定句中。
例句:It may rain tomorrow .明天可能会下雨。
例句:She may be at home.她可能在家呢.
3) may的过去式为might,表示推测,可能性低于may。
例句:He is away from school. He might be sick.他离开学校了,可能是他生病了。
4) 表示希望、祈求、祝愿,常可译为“祝愿”。句型通常是may +主语+动词原形。
例句:May you have a good time.祝你过得愉快。
例句:May you be happy! 祝你幸福!
例句:May you succeed!祝你成功!
4. must的用法:
1) must表示主观看法,意为“必须、一定”。
例句: You must stay here until I come back.在我回来之前你必须呆在这儿。
例句:Must I hand in my homework right now?我必须现在交作业吗?
2) 其否定形式mustn’t表示 “禁止,不准,不允许”、“一定不要”、“千万别”。
例句:You mustn’t play with fire. 你不许玩火。
例句:You mustn’t be late.你一定不要迟到。
3) must表示有把握的推测,“肯定”,用于肯定句。
例句:The light is on, so he must be at home now. 灯亮着,他现在肯定在家。
4) 对must引导的疑问句回答
①肯定回答为must
②否定回答为needn’t 或don’t have to
例句:—Must I finish my homework?我现在必须完成作业吗?
—No, you needn’t./ No, you don’t have to. 不,你不必。
注意must反意问句的构成形式:
当must表示肯定的判断、推测时,其反意疑问句要用实际问句的助动词来反问。
例句:She must have seen the film before,hasn’t she?
例句:You must have met uncle Wang in the shop yesterday,didn’t you?
5. need的用法:
1) need表示需要、必须,主要用于否定句和疑问句中。
2) 用need提问的回答:
肯定回答为must,否定回答为needn’t“没有必要”或don’t have to“不必”。
例句: —Need I stay here any longer? 我还有必要留在这儿吗?
—Yes, you must .是的。
—No. you needn’t /don’t have to.不,你不必。
3) need还可以作实义动词,此时有人称、数和时态的变化。
① 如果是人作主语后边多接动词不定式,即need to do。
例句:I need to do it at once.我需要马上做这件事。
例句:He needs to learn more about the girl.他需要多了解那个女孩。
② 如果是物作主语,一般用need doing与need to be done。
例如:The door needs painting. = The door needs to be painted.
那扇门需要刷一下漆。
例句:Your car needs repairing. = Your car needs to be repaired.
你的车需要维修了。
6. shall的用法:
shall表示征求对方意见(多用于第一、三人称)。
例句:Shall we go out for a walk?我们出去散步好吗?
其回答方式有以下几种:Yes, please. All right. No, thank you.
在英语中,我们可以用其他多种方式提出我们的建议或征求对方意见。
1) 用“Let's do...”来提出建议。
例句:Let's go for a walk after supper.我们晚饭后去散步吧。(和听话者一起散步)
例句:Let us go for a walk after supper.请让我们晚饭后去散步吧。(征求听话者意见)
2) 用“What/How about...?”来提出建议;about后接名词或doing形式。
例句:What about/How about a drink? 喝一杯怎么样?
例句:What about/How about taking Tom with us?带上汤姆和我们一起怎么样?
3) 用“Why not...?”来提出建议,表示“何不……”not面后接动词原形。“Why not...?”实际上是“Why don't you/we...?”的简略形式。
例句:Why not meet at the school gate at eight? 不如八点在校门口见吧?
例句:Why don't we stay here another day? 我们何不改天留在这里?
4) 用“Would you like...?”来提出建议,意思是“你想要……吗?”Would you like后可接名词或to do。
例句:Would you like a cup of tea?你想喝杯茶吗?
例句:Would you like to go and see her?你想去看看她吗?
因此,如果我们说:“去游泳好吗?”英语中可有这样几种表达法:
Shall we go for a swim?
Let's go for a swim,shall we?
What about/How about going swimming?
Why not go for a swim?
Would you like to go for a swim?
What do you think of going for a swim?
would you… 的回答方式有以下几种:
A. Yes, I will. (No, I won’t.)嗯,好的。(不,不必了。)
B. Sure . (I’m sorry , I can’t.)当然。(抱歉,不能。)
C. All right. / OK. / With pleasure./Certainly. (No, thank you .)好的。/乐意效劳。/当然。(不,谢谢。)
D. Yes, please.好的,麻烦了。
【例题】—Would you give me a hand and pass on my thanks to Lily?
—________.
A. That’s right B. With pleasure C. It doesn’t matter D. No trouble
7. should的用法:
1) should意为“应该”,可表示劝告、建议、义务、责任等。
例句:We should protect the environment.我们应该保护环境。
2) should have done过去本应当做某事但却没有做,表示对过去动作的责备、批评。
例句:You should have finished your homework by now.
3) 到目前为止你应该已经完成作业了。(事实上你没有完成。)
8. will的用法:
will表示意愿、意志、打算,可用于多种人称。
例句:I will help you if I’m free this afternoon.
今天下午如果我有空,我就会帮你。
9. had better的用法:
had better意为“最好”,没有人称的变化,后面接不带to的不定式,
其否定形式为:had better not。
例句:We had better go now.我们最好现在就走。
例句:You had better not give the book to him.你最好不要把这本书给他。
情态动词练习题
一、选择题
( ) 1. John___ come to see us tonight, but he isn't very sure yet.
A. may B. can C. has to D. must
( ) 2. They ___ do well in the exam.
A. can be able to B. be able to
C. can able to D. are able to
( ) 3. -May I take this book out?
-No, you___.
A. can't B. may not C. needn't D. aren't
( ) 4. You___ go and see a doctor at once because you're got a fever.
A. can B. must C. dare D. would
( ) 5. -Can you speak Japanese?
-No, I____.
A. mustn't B. can't C. needn't D. may not
( ) 6. -He___ be in the classroom, I think.
-No, he ___ be in the classroom. I saw him go home a minute ago.
A. can; may not B. must; may not C. may; can't D. may; mustn't
( ) 7. Even the top students in our class can't work out this problem, so it___ be very difficult.
A. may B. must C. can D. need
( ) 8. He isn't at school. I think he ___ be ill.
A. can B. will C. must D. has to
( ) 9. ___ I take this one?
A. May B. Will C. Are D. Do
( ) 10. The children___ play football on the road.
A. can't B. can C. mustn't D. must
( ) 11. You ___ be late for school again next time.
A. mustn't B. needn't C. don't have to D. don't need to
( ) 12. -Must I do my homework at once?
-No, you___.
A. needn't B. mustn't C. can't D. may not
( ) 13. His arm is all right. He___ go and see the doctor.
A. has not to B. don't have to C. haven't to D. doesn't have to
( ) 14. He had to give up the plan, ___ he?
A. did B. didn't C. does D. doesn't
( )15. —Must I return the hook tomorrow morning?
—No, you _____ .You can keep it longer.
A. mustn't B. can't C. needn't D. couldn't
( )16. —How long may I keep the book?
—You ________ keep it for two weeks.
A. may B. must C. will
( )17. — Susan, would you like to go hiking with us this afternoon?
— I'd love to, but I study for a test.
A. may B. have to C. can
( )18.-- May I go out now, Dad?
-- No. You __ let your mother know first.
A. can B. may C. need D. must
( )19. - Can I skate on the lake now?
- No, you ______. It’s dangerous.
A. can’t B. mustn’t C. needn’t D. won’t
( )20. —Peter doesn’t mind lending you his camera.
—He __________. I’ve already borrowed one.
A. needn’t B. can’t C. mustn’t D. shouldn’t
( )21. — Good morning. I've got an appointment with Ms King in her office.
— Morning. You _______be Mr. Jones. This way, please.
A. will B. must C. can D, might
( )22. ----Dad, the bread is not enough. I am still hungry. I have something more?
----But there’s nothing in the fridge now.
A. Must B. Need C. Will D. Can
( )23. —Where's my music disc? I can't see it!
—You'd better the disc carefully in your bedroom.
A. look up B. look through C. look for
( )24. --- Do we have to go to school this afternoon?
--- Yes, you ________.
A. must B. can C. need
( )25. — Congratulations! You've got the first prize in the English Contest.
—_____ it be true? It's unbelievable!
A. May B. Should C. Must D. Can
( )26. ---May we go home now ?
--- No, you____. You____ to go home until 5 o’clock.
A. mustn’t; are allowed B. don’t have to; are supposed
C. needn’t; aren’t allowed D. can’t; aren't supposed
二、 填空题:
1. —Must we leave now?
—No, we _______ _______ _______.We still have two more hours.
2. — Can you ride a horse?
— No. I____ .
3. You eat the soup if you don't like it.
4. ________ you wait a few more minutes? He will return soon.
5. —May we leave the classroom now?
—No, you_________. You shouldn't leave until the bell rings.
6. She _______ be here . I saw her come in.
7. I can’t go to the cinema with you because I ___________ stay here until my mother comes back.
8. —Be quiet, Mr. Smith is coming.
—Don’t worry. It __________ be him. Mr. Smith is much taller.
9. —________ I smoke here?
—No. You are not allowed to smoke in public places.
10. —Hey, Ted! You _______ never play in the street. It’s not safe.
—Sorry, Mum. I won’t again.
11. —Whose T - shirt is this?
—It______ be John' s. It ‘s ______ _______small for him.
12. — Must we clean the classroom at once?
— No, you _______. You _______ clean it after school.
13. —I can’t stop smoking, doctor.
— For your health, I’m afraid you _______ _______.
14. --Shall we meet at the station at 8 am?
--In fact we _____ ______. The train until 10 am.
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