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情态动词的用法1 分类:1.只做情态动词:can(could)、may( might)、must.后接动词原形。2.可做情态动词又可做实义动词。如:need,dare3.具有情态动词特征:have(has,had)to,used to(过去常常)。2 情态动词的用法:情态动词后接动词原形1. must的用法1)must意为“必须;应该;一定”。表示说话人的主观意志,表示必须要做的。如:We must finish reading the book in two weeks. 我们必须在两周内看完这本书。2)表示说话人对事物的推测,语气比may肯定,只用于肯定句中。Must be译为“一定是”如:Mr. Liu must be in the office. 刘老师一定在办公室。3) 用must提问时,如果是否定回答,多用neednt或dont have to,表示“不必,没必要”,而mustnt表示“绝对不行,不可以,禁止”的意思。如:-Must I finish my homework now?-Yes,you must. -No,you neednt/dont have to4)have to意为“必须;不得不”,有人称、时态和数的变化,后跟动词原形,表示客观需要。如:When I was your age,I already had to work. 2. can的用法:1)can意为“能;会;可以”。表示能力,其否定式是cannot=cant。如:She can sing. 她会唱歌。2)表示请求许可。Can I . ? 意思是“我可以吗?”,较口语化。3)can的过去式是could,如:Lucy could swim at the age of five. 露西五岁时就会游泳了。could也可表示较can更为委婉的语气。如:Could you help me? 帮帮我好吗?4)can表示推测时,常用于否定句和疑问句中。Cant be“不可能是”,若是疑问句,其肯定回答用may或must。如:Where can it be? 它会在哪里呢?It may/must be in your desk . 它可能/一定在你的课桌里。否定回答:It cant be in your desk.它不可能在你的课桌上。3. may的用法:1)may意为“可以;可能”。表示请求、许可。如:May I look at your CD player? 我可以看一下你的CD机吗?2)表示可能性(说话人的猜测),常用于肯定句中。如:Your sister may be waiting for you now. 你妹妹可能现在正在等你呢。3) 以may引起的一般疑问句,否定回答多用mustnt;May I come in? 我可以进来吗?No, you mustnt. 不,不行。4.need的用法:1)need作情态动词时,意为“需要”,后接动词原形,常用于疑问句和否定句中,否定形式:neednt,疑问句:Need提前如:You neednt try to explain. Need I explain it?2) need作为实义动词时,后接动词不定式to do,有人称和数的变化。如:She needs to come tomorrow.He (不需要)borrow money.Do they_(需要)do homework today?5. had better的用法:had better(not) do sth 最好(不要)做某事如:Youd better _(stay) at home. Youd better _(not watch) TV.练习: ( ) 1 John_ come to see us tonight, but he isnt 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. 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( ) 5 -Can you speak Japanese?-No, I_.A. mustnt B. cant C. neednt D. may not( ) 1 -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( ) 2 -Shall I get one more cake for you, Dad?-Thanks, but you_, Ive had enough.A. may not B. must not C. cant D. neednt( ) 3 Even the top students in our class cant work out this problem, so it be very difficult.A. may B. must C. can D. need( ) 4 He isnt at school. I think he _ be ill. A. can B. shall C. must D. has to( ) 5 _ I take this one? A. May B. Will C. Are D. Do( ) 1 The children_ play football on the road.A. cant B. can C. mustnt D. must( ) 2 You _ be late for school again next time.A. mustnt B. neednt C. dont have to D. dont need to( ) 3 -Must I do my homework at once?-No, you_. A. neednt B. mustnt C. cant D. may not( ) 1 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( ) 2 He had to give up the plan, _ he? A. did B. didnt C. does D. doesnt( ) 3 They had to walk here, _ they? A. mustnt B. did C. didnt D. hadnt( ) 1 He had better stay here, _ he? A. didnt B. dont C. hadnt D. isnt( ) 2 Youd better_late next time. A. not to be B. not be C. wont be D. dont be( ) 3 Youd better _ your hair _ once a month.A. had; cut B. had; cutted C. have; cut D. have; cutted( ) 4 You_ ask that man over there. Maybe he knows the way. A. had better not to B. had not better C. had better D. had better not( ) 1 -Shall we go and visit the History Museum next Sunday?A. Here you are B. Sorry, I cant C. Yes, please D. Let me try( ) 2 -Why dont you ask Mike to go with us?-Thanks, _.A. I will B. I wont C. lean D. I may( ) 3 -_ I take the newspaper away?-No, you mustnt. You_read it only here.A. Must; can B. May; can C. Need; must D. Must; must( ) 1 Excuse me. _ you please pass me that cup?A. Do B. Should C. Would D. Must( ) 2 _ you like to have another try?A. Could B. Will C. Would D. Do( ) 3 -Would you like to go boating with us?-Yes, _.A. Id like B. I want C. Id like to D. I do( ) 1 You_ worry about your son. He will get well soon.A. neednt B. cant C. mustnt D. have to( ) 2 The poor man needs our help, _ he?A. need B. neednt C. does D. doesnt( ) 3 -Must we do our homework first?-No, you_. You may have a rest first.A. mustnt B. neednt C. may not D. cant参考答案:1. 1-5 A D A B B2. 1-5 C D B C A3. 1-3 C A A4. 1-3 D B C5. 1-4 C B C C6. 1-3 B A B7. 1-3 C C C8. 1-3 A D B
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