1、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: 不能单独做谓语,必须与其他动词一起构成谓语; 没有人称和数的变化; 情态动词后必须跟动词原形; 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 cant . 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m
2、ay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cant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 cant be our teacher. He is visiting the Great Wall. 不
3、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. cant B. mustnt C. neednt D. wouldnt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 abl
4、e 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 h
5、and? 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. Would2) 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
6、 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
7、“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mustnt表示 “禁止,不准,不允许”、“一定不要”、“千万别”。例句:You mustnt play with fire. 你不许玩火。例句:You mustnt 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
8、现在肯定在家。4) 对must引导的疑问句回答 肯定回答为must否定回答为neednt 或dont have to 例句:Must I finish my homework?我现在必须完成作业吗? No, you neednt./ No, you dont 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,hasnt she?例句:You must have met uncle Wang in the shop yesterday,
9、didnt 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neednt“没有必要”或dont 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 neednt /dont 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。 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
10、做这件事。例句:He needs to learn more about the girl.他需要多了解那个女孩。 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 w
11、alk?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“Lets do.”来提出建议。例句:Lets 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 drin
12、k? 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 dont 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 dont 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 lik
13、e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?Lets 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 s
14、wim?would you 的回答方式有以下几种:A. Yes, I will. (No, I wont.)嗯,好的。(不,不必了。)B. Sure . (Im sorry , I cant.)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. Thats right B. With p
15、leasure C. It doesnt matter D. No trouble7. 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 wi
16、ll help you if Im 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 isnt very sure yet.A. may
17、 B. can C. has to D. must( ) 2. They _ do well in the exam.A. can be able to B. be able toC. can able to D. are able to( ) 3. -May I take this book out?-No, you_.A. cant B. may not C. neednt D. arent( ) 4. You_ go and see a doctor at once because youre got a fever.A. can B. must C. dare D. would( )
18、5. -Can you speak Japanese?-No, I_.A. mustnt B. cant C. neednt 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; cant D. may; mustnt( ) 7. Even the top students in our class cant work out this pr
19、oblem, so it_ be very difficult.A. may B. must C. can D. need( ) 8. He isnt 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. cant B. can C. mustnt D. must( ) 11. You _ be late for sch
20、ool again next time.A. mustnt B. neednt C. dont have to D. dont need to( ) 12. -Must I do my homework at once?-No, you_. A. neednt B. mustnt C. cant D. may not( ) 13. His arm is all right. He_ go and see the doctor. A. has not to B. dont have to C. havent to D. doesnt have to( ) 14. He had to give u
21、p the plan, _ he? A. did B. didnt C. does D. doesnt( )15. Must I return the hook tomorrow morning? No, you _ .You can keep it longer. A. mustnt B. cant C. neednt D. couldnt( )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 hikin
22、g with us this afternoon? Id 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 _. Its dangerous.A. cantB. mustntC. needntD. wont( )20. Peter doesnt
23、 mind lending you his camera.He _. Ive already borrowed one.A. needntB. cant C. mustnt D. shouldnt( )21. Good morning. Ive 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 hungr
24、y. I have something more? -But theres nothing in the fridge now. A. Must B. Need C. Will D. Can ( )23. Wheres my music disc? I cant see it!Youd 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. c
25、an C. need( )25. Congratulations! Youve got the first prize in the English Contest._ it be true? Its unbelievable!A. May B. Should C. Must D. Can( )26. -May we go home now ? - No, you_. You_ to go home until 5 oclock. A. mustnt; are allowed B. dont have to; are supposedC. neednt; arent allowed D. ca
26、nt; arent 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 dont like it.4. _ you wait a few more minutes? He will return soon.5. May we leave the classroom now?No, you_. You shouldnt leave until the bell rings.
27、6. She _ be here . I saw her come in.7. I cant go to the cinema with you because I _ stay here until my mother comes back.8. Be quiet, Mr. Smith is coming.Dont 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 p
28、lay in the street. Its not safe. Sorry, Mum. I wont 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 cant stop smoking, doctor. For your health, Im afraid you _ _.14. -Shall we meet at the station at 8 am? -In fact we _ _. The train until 10 am.