人教新课标必修三 Unit 2 Healthy eating[情态动词]

1、主要情态动词主要情态动词 can, could may, might must/have to need dare will/would shall/should/ought to what modal verbs have you learned?1. 情态动词有一定的意义，只表示情态动词有一定的意义，只表示期待期待或或估计估计某事的发生，某事的发生，不能表示正在发生或已经发生的事情。不能表示正在发生或已经发生的事情。 2. 没有人称和数的变化没有人称和数的变化，即情态动词第三人称单数不加，即情态动词第三人称单数不加-s。 3. 不能独立使用不能独立使用，它和后面的动词构成谓语。，它和后面的

2、动词构成谓语。4. 情态动词情态动词 除除ought 和和have 外外，后面只能接动词原形，后面只能接动词原形5. 情态动词情态动词没有非谓语形式没有非谓语形式，即没有不定式，分词等形式。，即没有不定式，分词等形式。 只作情态动词的只作情态动词的 can/could, may/might, ought to, must可情态可实义的可情态可实义的 need, dare可情态可助动词的可情态可助动词的shall/should, will/would相当于情态动词的相当于情态动词的have to情态动词的语法特征情态动词的语法特征情态动词情态动词 含义含义否定式否定式注意点注意点must表必要表

3、必要“必须必须”neednt“不必不必”( 区别区别 have to)有时表有时表“偏要偏要”表推测表推测“一定一定” cant“不可不可能能”只能只能用于用于肯定肯定句，句，不能不能用于用于否定、疑问句否定、疑问句1.must & need & have to 注意：注意：1) must 表示推测时，表示推测时， 只能用于只能用于肯定句。肯定句。must do 对对一般时一般时的肯定推测的肯定推测must have done 对对过去发生的事情过去发生的事情作出的肯定判断作出的肯定判断must be doing 对对现在的动作现在的动作进行肯定推测进行肯定推测 e.g. 他们

4、买了一辆新车。他们买了一辆新车。 他们一定很有钱他们一定很有钱they have bought a new car. they must have a lot of money.他现在一定在看小说他现在一定在看小说he must be reading novels now.路是湿的。昨天晚上一定下雨了。路是湿的。昨天晚上一定下雨了。the road is wet. it must have rained last night.- need he start from the beginning? - yes, he must. - no, he neednt/doesnt have to. 1

5、.作作情态动词情态动词时时,仅用于否定或疑问句仅用于否定或疑问句,后接动词原形后接动词原形,表表“需要需要”2) need you neednt return the book now.2.neednt have done 表示做了本不必要做的事情表示做了本不必要做的事情,意为意为“本不必要本不必要”our color tv set is still good enough. you neednt have bought a new one.3.作作实义动词实义动词时时,表示表示“需要需要”，有人称、时态、和数的变，有人称、时态、和数的变化化he needs to finish it this

6、 evening. the classroom needs cleaning.4 注意对注意对need问句的回答问句的回答: -need i finish the work today? -yes, _. no, _. no, _.you mustyou needntyou dont have toneednt 对其它情态动词的回对其它情态动词的回答答:-shall i tell john about it?-no, you _.-no, you _. -must we do it now? -no, you _.-no, you _.needntdont have toneedntdont

7、have to情态动词情态动词 含义含义否定式否定式 注意点注意点can / could表能力表能力“能能/会会”cant“不会，不能不会，不能”区别区别 be able to表许可表许可“可以可以”cant “不可以，不许不可以，不许”代替代替may表推测表推测“可能可能”cant “不可能不可能”主要用于主要用于否定否定/疑问句疑问句中中1 表示某人通过努力克服困难做成某事表示某人通过努力克服困难做成某事,要用要用was / were able to.2 could, might, would 表委婉语气用于疑问句表委婉语气用于疑问句, 答语仍须用答语仍须用 can, may, will.

8、3 can 用于肯定句中用于肯定句中, 可表示可表示”有时可能有时可能”2. can/could 4. can/could have done “本可以，本可能做某事本可以，本可能做某事” 用于用于肯定句肯定句中，表示对中，表示对过去发生的事情过去发生的事情做出的判断。做出的判断。 你本来可以考的更好。你本来可以考的更好。you could have had a better mark.5. can/could not have done 对对过去发生过去发生行为进行推行为进行推测测:不可能做某事不可能做某事1) 刚才我还看见他了，刚才我还看见他了， 所以他不可能出国的。所以他不可能出国的。

9、i saw him just now so he couldnt have gone abroad.2) 门是锁着的，门是锁着的， 所以她不可能在家。所以她不可能在家。the door was locked，so she couldnt have been at home. 情态动词情态动词 含义含义否定式否定式 注注 意意 点点may /might表许可表许可“可以可以”mustnt “不许，严禁不许，严禁”口语中也可用口语中也可用cant表推测表推测“可能可能”cant “不可能不可能”主要用于主要用于肯定肯定句，句，不能用在不能用在疑问疑问句句 （may not 可能不）可能不）3.ma

10、y/might注意：注意：might/may have done,表示对表示对过去发生的动作过去发生的动作进行可进行可能性推测，能性推测， 1）他可能去医务室了。）他可能去医务室了。he may have gone to the clinic.2）他可能已经从报纸上知道这个消息了。）他可能已经从报纸上知道这个消息了。he might have read about the news in the newspaper.1. -may i use your pencil? -yes, you may. / no, you mustnt.2. she may not be working now.

11、3. john might be at home now.4. helen may go on the trip with us, but she isnt very sure yet.5. she may / might have read it in the paper.6. he may not have finished reading the book.情态动词情态动词 用用 法法will表请求表请求(第二人称第二人称)表意志表意志,意愿意愿表某种倾向表某种倾向或习惯或习惯would更客气的更客气的请求请求过去的意志（愿）过去的意志（愿）过去的倾向过去的倾向或习惯或习惯4.will/

12、would情态动词情态动词 用用 法法shall征求对方意见征求对方意见(第一第一, 三人称三人称)表示命令表示命令,警告警告, 威胁或威胁或允诺允诺 (第二第二, 三人称三人称) should / ought to表示劝告表示劝告,建议建议,命令或责任命令或责任“应该应该, 必须必须”表示推测表示推测, “理应理应, 估计估计, 大大概概, 可望可望”should 还可还可表示表示“竟然竟然”5.shall ,should 和和ought toyou shall do as i say. (命令命令)1.在陈述句中在陈述句中,shall用于二、三人称表示允诺、警告、用于二、三人称表示允诺、警

13、告、命令、决心等。命令、决心等。shall i open the window for you？（征求意见）？（征求意见）2.在疑问句中在疑问句中,用于一、三人称，用来表示请求或征用于一、三人称，用来表示请求或征求意见。求意见。注意：注意：tell him that he shall have the book tomorrow. (允诺允诺)nothing shall stop me doing it. (决心决心) shall he fetch some water for you？（请求）？（请求）young people should learn how to use computer

14、s. 3. should常表示劝告、建议、命令，与常表示劝告、建议、命令，与ought to意意义相近，但义相近，但ought to多表示责任、义务，语气强烈。多表示责任、义务，语气强烈。every citizen ought to obey law. you ought not to go.you should/ought to have told her the truth earlier. she shouldnt have left without saying a word.4.should/ought to have done表示责备或批评表示责备或批评,意意为为“本应该本应该但但

15、”,ought to的语气更强烈的语气更强烈,用于否定用于否定则表示则表示“本不该本不该但但”5.should用于可能性推测时用于可能性推测时,表表“应该，很可能应该，很可能”they left at 5:30. they should get there now.1.作为情态动词情态动词用，常用在否定句否定句和疑问句疑问句中。dare (need) +s +vs + darent (neednt) +vi darent walk through the forest at night.dare you walk through the forest at night?you neednt r

16、eturn the book now.need he go yesterday?6.可兼做行为动词的情态动词：可兼做行为动词的情态动词：need 、 dare 判断正误判断正误: how dare you say such a thing? how dare you to say such a thing?he darent to speak english before such a crowd, did he?he darent speak english before such a crowd, dare he?nobody need to be afraid of catching t

17、he disease.nobody need be afraid of catching the disease.2.作实义动词实义动词用，常用在肯定句肯定句中, 有人称、时态、和数的变化he needs to go there himself.he has grown up,so we dont need to worry about him. 3.sth (sb) need( want, request)+ doing/ to be done the house needs cleaning/ to be cleaned the boy needs sending to the hospi

18、tal at once.表示推测表示推测情态动词的重要用法情态动词的重要用法肯定的推测肯定的推测可能的推测可能的推测否定的推测否定的推测疑问的推测疑问的推测must 对将来对将来 对现在对现在 对过去对过去情态动词情态动词may, might cant, couldntcan, could + v. + v. + have done常见常见must be + be doing + v. + v. + have done + be doing 可以用可以用not表示表示“可能不可能不” +v. + v. + have done + be doing+ v. + v. + have done +

19、be doing八八“情态动词情态动词+have done”用法用法情态动词情态动词+have done用法用法例句例句must have done 1.she must have gone through a lot.2.he must have visited the white house during his stay in the united states.may/might have done1.you may have learnt the news.2.he may not have heard his name called.3.sorry im late. i might

20、 have turned off the alarm clock and gone back to sleep again.canhave donecannot have done1.where can she have gone?2.could he have done such a foolish thing?3.the boy cant have finished reading the book so sooncould have done1.he could have killed himself driving at a dangerous speed.2.you could ha

21、ve done better, but you were too careless.might have done1.you should not swim in that sea. you might have been eaten by a shark.2.he might have given him more help, thought he was busy.表示对过去已经发生的行为进行表示对过去已经发生的行为进行肯定肯定推测，意为推测，意为“想必，准是，想必，准是，一定做了某事一定做了某事”只用于只用于肯定句肯定句表示对过去已发生行为的表示对过去已发生行为的可能可能推测，意推测，意

22、为为“也许也许/或许已经（没有）或许已经（没有）“。一。一般用于肯定句或否定句中，不用于疑问般用于肯定句或否定句中，不用于疑问句。用句。用might则表示语气更加不肯定。则表示语气更加不肯定。表示对过去发生的行为的怀疑和不肯定，表示对过去发生的行为的怀疑和不肯定，通常用在否定句和疑问句中。（通常用在否定句和疑问句中。（can换成换成could时语气委婉）时语气委婉）可用于肯定句中，表示可用于肯定句中，表示“可能已可能已经经”之意，此外，还可以表示过之意，此外，还可以表示过去能做而没做的事，有一种对过去为去能做而没做的事，有一种对过去为付诸实施的事情的惋惜。付诸实施的事情的惋惜。表示表示“本来可

23、能本来可能，但实际上没有发，但实际上没有发生的事情生的事情”。另外，还可以表示。另外，还可以表示“本来本来应该或可以做某事应该或可以做某事”之意，含有轻微的之意，含有轻微的责备语气。责备语气。should/ought to have done1.he should have known that the police would never allow this sort of thing.2.you ought not to have refused his offer.neednt have done1.you neednt have watered the plants, for it

24、is going to rain.had better have done1.you had better have started earlier.2.you had better not have scolded her.would rather have done1i would rather have taken his advice.2i would rather not have told him the truth.用于肯定句时，表示本该做某事，用于肯定句时，表示本该做某事，而实际上未做；用于否定句时，而实际上未做；用于否定句时，则表示不该做的事反而做了。则表示不该做的事反而做了

25、。表示做了本来不必去做的事。表示做了本来不必去做的事。用于事后的建议，含轻微责备的用于事后的建议，含轻微责备的口吻，意为口吻，意为“当时最好做了某当时最好做了某事事”，其否定式，其否定式had better not have done表示相反的含义。表示相反的含义。表示表示“当时宁愿做了某事当时宁愿做了某事”，其否定式其否定式would rather not have done表示相反的含义，表示相反的含义，两者都表示两者都表示“后悔后悔”之意。之意。1the thief _ in from the kitchen window as the door was closed. a. may c

26、limb b. must have climbed c. could have climbedd. should have climbed2i posted the letter a week ago. then they _ the letter by now. it usually takes four days. a. can have received b. must receive c. should received. ought to have receive3.there were already five people in the car, but they managed

27、 to take me as well. it _ a comfortable journey. a. cant b. shouldnt be c. must have been d. couldnt have beeni. try to explain the meanings of the modal i. try to explain the meanings of the modal verbs in the following sentences.verbs in the following sentences.1.he can speak english well.2.you ca

28、n go home now.3.that cant be true.4.could you please show me the way to beihai park?5.they hunters are lost. they could starve.6. may i come in?7. he may give you some help?abilityabilitypermissionpermissionguessingguessingrequestrequestpossibilitypossibilitypermissionpermissionpossibilitypossibilit

29、y8.dont worry. i will help you.9.often he would dress up like a rich man.10.would you like to join us for dinner?11.you shall have the ticket as soon as i get it.12.you should arrive at the airport two hours before he goes.13.it is five oclock. he should turn up soon.14.wang feng wins an award every

30、 year. he must be misepromisepast habitrequestpromisepredictionadviceguessing2. 用情态动词完成句子用情态动词完成句子1).youve been working all day. you_ be very tired.2).(the doorbell rings) i wonder who that is. it _ be lisa. shes still in the library at this time.3).it is a long time since we met last time

31、. you _ come and see us more often. mustcantshould4.i havent decided where im going for my holidays. i _ go to australia.5.my fathers birthday is ccoming. what _ i give him?6.why dont you try on this dress? it _ look nice on you.mayshallwill7. “who was the man talking with your teacher?” “im not sur

32、e. it _ be her brother.”8.i dont know when the guests _be here. they _arrive at any time. mightwillcould3.完成下列句子：完成下列句子： 1. i dont know where she is, she _. (可能在武汉）可能在武汉）(be)2. at this moment, our teacher _（想必在批改）（想必在批改）our exam papers. ( mark / grade)3. the road is wet. it _(一定下雨了）一定下雨了） last night

33、. (rain) 4. your mother _ （一定一直在找你）（一定一直在找你）(look)may be in wuhan gradingmust be marking must have rainedmust have been looking for you.5. philip _ seriously in the car accident. (可能受了重伤可能受了重伤). (hurt)6. -linda has gone to work, but her bicycle is still here. -she _(可能走了可能走了)by bus.(go)7. mike _(一定还

34、没有找回一定还没有找回)his car, for he came to work by bus this morning.may (might) have been hurtmay (might) have gonecant have found4.multiple-choice1. isnt that anns husband over there? no, it _ be him. im sure he doesnt wear glasses. (04全国全国i 29) a. cant b. must not c. wont d. may not2. ill tell mary about

35、 her new job tomorrow. you _ her last week. (04福建福建32) a. ought to tell b. would have told c. must tell d. should have told3. i often see lights in that empty house. do you think i _ report it to the police? (04广西广西21) a. should b. may c. will d. can4. mr. white _ at 8:30 for the meeting, but he did

36、nt show up. (04广西广西27) a. should have arrived b. should arrive c. should have had arrived d. should be arriving5. excuse me. is this the right way to the summer palace? sorry, i am not sure. but it _ be. (04湖北湖北26) a. might b. will c. must d. can6. excuse me, but i want to use your computer to type

37、a report. you _ have my computer if you dont take care of it. (04湖南湖南28) a. shant b. might not c. neednt d. shouldnt7. i dont mind telling you what i know. you _. im not asking you for it. (04江苏江苏22) a. mustnt b. may not c. cant d. neednt8. mum, ive been studying english since 8 oclock. _ i go out a

38、nd play with tom for a while? no, im afraid not . besides, its raining outside now. (04辽宁辽宁29) a. cant b. wouldnt c. may not d. wont9. you _ be tired youve only been working for an hour. (04全国全国ii 29) a. must not b. wont c. cant d. may not10. children under 12 years of age in that country _ be under adult supervision when in a public library. (04上海上海28) a. must b. may c. can d. need11. who is the girl standing over there? well, if you _ know, her name is mabel. (04天津天津31) a. may b. ca