情态动词专题

1 情态动词2The feature（特点）of the modal verbs:1.情态动词本身有词义情态动词本身有词义,但词义不完全但词义不完全.2.不能单独作谓语不能单独作谓语,只能和动词原形一起构成谓语只能和动词原形一起构成谓语.3.情态动词没有人称和数的变化情态动词没有人称和数的变化(除除“have to”外外).4.没有不定式、没有不定式、-ing 分词、分词、-ed 分词形式分词形式.He can/could/must/may/might/shall/should/need/dare/will/would/ought to/used to/had better/would rather+work in that factory.He has to go home now.He had to look after his sick mother.I will have to go home because my mother is ill.3 情态动词的运用是高考英语单项选情态动词的运用是高考英语单项选择几乎每年必考的要点。根据近几择几乎每年必考的要点。根据近几年对全国和各省市的部分高考题和年对全国和各省市的部分高考题和质检题分析，主要归纳为以下几个质检题分析，主要归纳为以下几个考查热点：考查热点：1.情态动词表示推测情态动词表示推测 2.情态动词情态动词+have done 结构；结构；3.情态动词基本用法情态动词基本用法.4 一、用法一、用法 从高考及平时各类考试情态动词的推测用法从高考及平时各类考试情态动词的推测用法来看，主要有来看，主要有must,should,can(could),may(might)几个词，现对它们的用法按可能几个词，现对它们的用法按可能性从大到小排列列表如下：性从大到小排列列表如下：mustshould cancouldmay might肯定句肯定句must should can could may might否定句否定句cant couldnt疑问句疑问句can could5 一、用法一、用法一般式：must/should/can/could/may/might do sth.进行式：must/should/can/could/may/might be doing sth.完成式：must/should/can/could/may/might have done sth.6例题1.这一定是这一定是Baker 先生。先生。2.马丽不可能去过国外。马丽不可能去过国外。3.妈妈可能正在房间里睡觉。妈妈可能正在房间里睡觉。_ it be Dr Baker?(可能是可能是Baker 博士吧？）博士吧？）CanIt Mr.Baker.Mary abroad.Mum in the roommust becant have beenmight be sleeping7 1表推测时，表推测时，might不是不是may的过去式，的过去式，could不是不是can的过去时，而是表示的过去时，而是表示might/could的可能性比的可能性比may/can还小，所以，上述情态动词的过去式并不还小，所以，上述情态动词的过去式并不表示对过去的情况进行推测。表示对过去的情况进行推测。2should表示根据事物内在发展的规律、事情发表示根据事物内在发展的规律、事情发展的必然性得出的结论，表示展的必然性得出的结论，表示“某人（某事）按道某人（某事）按道理应该（理应）理应该（理应）”。3can/could常用于否定句和疑问句中表示推测，常用于否定句和疑问句中表示推测，但在表示但在表示“有时候可能有时候可能”或或“从理论上讲从理论上讲”时，也时，也可用于肯定句中。可用于肯定句中。4may/might not用于否定句中表用于否定句中表“可能不可能不”，而，而不是不是“不可能不可能”。8 1.He _ have completed his work;otherwise,he wouldnt be enjoying himself by the seaside.(2009北京卷)A.shouldB.must C.wouldntD.cant 2.This cake is very sweet.You _ a lot of sugar in it.（2005辽宁卷）A.should putB.could have put C.might put D.must have put 3.Is John coming by train?He should,but he _ not.He likes driving his car.(NMET2002)A.mustB.can C.need D.may9 4.My English-Chinese dictionary has disappeared.Who _ have taken it?（2010上海春季）A.shouldB.mustC.couldD.would 5.When can I come for the photos?I need them tomorrow afternoon.They _ be ready by 12:00.（NMET1998）A.canB.shouldC.mightD.need 6.Isnt that Anns husband over there?No,it _ be himIm sure he doesnt wear glasses.（NMET2004）A.cantB.must not C.wontD.may not10 7.Excuse me.Is this the right way to the Summer Palace?Sorry,I am not sure.But it _ be.（2009湖北）湖北）A.mightB.willC.mustD.can 8.My sister met him at the Grand Theatre yesterday afternoon,so he _ your lecture.（2008上海）上海）A.couldnt have attendedB.neednt have attended C.mustnt have attendedD.shouldnt have attended 9.Sorry,Im late.I _ have turned off the alarm clock and gone back to sleep again.（2008北京春季）北京春季）A.should B.can C.might D.will 10.Its nearly seven oclock.Jack _ be here at any moment.（NMET 1995）A.must B.needC.shouldD.can11情态动词+have done 1.must have done(过去)肯定/一定 (用于肯定句中)I didnt hear the phone.I must have been asleep.表示对过去对过去所发生事情的推测或带有某语气推测或带有某语气.12 There were already five people in the car,but they managed to take me as well.It couldnt have been a comfortable journey.He may not have finished the exercises,Im afraid.2.cant/couldnt have done (过去)不可能3.may/might have done(过去)或许/可能做(用于肯定或否定句中)13could have done(过去)本能够做(用于肯定或否定句中,带有责备、劝告之意)You could have done better,but you didnt try your best.情态动词情态动词+have done 本能够做本能够做neednt have done(过去)本来不必做 When we got to the cinema,the film hadnt started,so we neednt have worried.146.should/ought to have done(过去)本应该做(而实际上未做),用于否定句时则表示过去不该做的事反而做了(带有后悔、埋怨或责备的语气）。She shouldnt have taken away my tape,for I wanted to use it.15(04全国)Mr.White_ at 8:30 for the meeting,but he didnt show up.B.should arrive C.should had arrived D.should be arriving(10福建)Ill tell Marry about her new job tomorrow.You _ her last week.A.ought to tell B.could have told C.must tell A.should have arrived D.should have told16(08福建)Catherine,I have cleaned the room for you.Thanks.You _ it.I could manage it myself.A.neednt do C.mustnt do D.shouldnt have doneB.neednt have done17(NMET 05)He _ have completed his work;otherwise,he wouldnt be enjoying himself by the seaside.A.should C.wouldnt D.cantB.must18 can could1.表“能力”Can you lift this heavy box?I couldnt understand what he said at all.2.表“许可”基本同基本同mayYou can use a different material instead.He said I could borrow his bike.3.“怀疑”What on earth can this mean?1.can与与could用法用法 can could.swf How could you be so careless?194.表 “猜 测”a.can用于疑问句中:否定答案用cant;肯定答案用must.Can he be in the library?He cant be in the library.He must be at home.b.can+have+P.P.表示对过去的推测 (限于问句中).Can he have said so?他可能这样说吗?c.cant+have+P.P.表 示对过去的否定推测She cant have said such a foolish thing.她不可能说这样愚蠢的事.20d.could+have+P.P:表示本来能做得到,但事实上未做到.He could have finished the task on time,but the heavy snow came.e.couldnt+have+P.P表示对过去某事的否定性猜测He couldnt have been to that town.21注注:can not too+adj.译为译为“再再.也不为过也不为过”，.you can not be too cautious when you are driving in snow.can(能够)=be able to(仅表示能力时),但 be able to 表示经过一番努力后,才能做得到.且有更多的时态.He was a good swimmer,so he _ swim to the river bank when the boat sank.A.could B.might C.shall D.was able to D.was able to雪天驾驶，越小心越好雪天驾驶，越小心越好 22may与might用法:may might1.表“询问”May I?(=Can I?)Might I?(=Could I?)(但比用may更客气.)2.表“许可”You may take the boy thereHe told me he might come.(might与told 相呼应.)3.表“可能”“或许”She may not like this place.Im afraid he might not like this place.234.表“猜测”a.may(might)+V.表示对现在事情的猜测.(might比 may可能性更小一些.)Now he might know her address.Be careful,you might break the glass.b.may(might)+have+P.P,表示对过去事情的猜测,认为某事“可能”发生.(might比may更含蓄,或更不肯定.)He may(might)have played electric game on TV the whole night.(For he looks very sleepy.)24注注:may I?的答语.肯定:Yes,you may.否定:May you succeed!May you have good luck!No,you mustnt (语气强硬语气强硬)No,you may not.或或 No,youd better notmay用于祈用于祈使句中表示使句中表示祝愿祝愿may as well还不如，不还不如，不妨妨还是还是的好的好There is nothing to do,so I may as well go to bed 没什么事可做，我还是上床没什么事可做，我还是上床睡觉好了。睡觉好了。25must与 have to用法对比must have to1.表“必须”(主观看法)必须;没有过去式,可用于间接引语中.He told me I must do according to what he said.(客观需要)不得不;有多种时态.-Its raining heavily,we cant go now.-I think well have to wait till the rain stops.2.疑问句及答语中Must I?Yes,you must.(一定)No,you No,youDo you have to go today?Yes,we .No,You worry about that.neednt.dont have tododont have to26You must be hungry now,_?=Im sure you are hungry now.He must be watching TV now,_?=Im sure he is watching TV now.Tom must have lived here for a long time,_?=Im sure Tom has lived here for a long time.She must have arrived yesterday,_?=Im sure she arrived yesterday.*陈述部分的陈述部分的must表示表示“一定一定”,“想必想必”等等推测推测意意义时义时,要根据陈述部分的不定式结构要根据陈述部分的不定式结构,在反意疑问部在反意疑问部分采用与其相适应的主动词或助动词形式分采用与其相适应的主动词或助动词形式.arent youisnt hehasnt hedidnt she27should与与ought to用法对比用法对比should ought to1.表表“应应当当”表示劝告,建议You should listen to the doctors advice.We should learn from Zhang Hua.表示“有义务或有必 要”做某事You ought to finish your work before you go home.We ought to help each other.2.表表可能可能的猜的猜测测They should get home by now.表非常可能的事“总应该”If we start to work right now,we ought to finish it before lunch.283.表“责备”或“惋惜”Should Ought to+have+P.P.该做，而没有做Should not ought not to+have+P.P.不该做，而做了The plant is dead.I should have given it more water.You should not have left your baby alone in the house.注:1Should 用于虚拟语气用于虚拟语气I suggest that you should stay here as if nothing had happened.We should move to a larger house if we had the money.If I was asked to work on Sundays,I should resign.292.Ought to 疑问式及否定式Ought he to go?Yes,I think he ought(to).He ought not to leave the work tomorrow.(oughtnt to leave)303.shall1)作助动词，用于第一人称，表示将来，作助动词，用于第一人称，表示将来，should 是是shall 的过去式的过去式 We shall start for Beijing tomorrow.2)作情态动词，作情态动词，Shall we begin our lesson?Shall I sit here?A:用于一、三人称，表示征求用于一、三人称，表示征求对方意见或请求对方意见或请求311.You wanted justice,so you shall get justice,more than you wanted.(允诺，允诺，威尼斯商人威尼斯商人)2.You shall be sorry for what you have done,I tell you.（警告）（警告）3.When he comes in nobody shall say a word.(命令命令)4.Nothing shall stop us from carrying out this plan.(决心决心)B:用于二、三人称，表示允诺、警告、用于二、三人称，表示允诺、警告、威胁、命令、决心等。威胁、命令、决心等。32Need与与dare用法对比用法对比need dare1.情态动情态动词词+V *疑问式*否定式Need we do it again?No,you neednt do it again.Dare she go out alone at night?How dare you say I am unfair?He dare not say so.2.实义动词+to do *肯定式*否定式*疑问式He needs to go.He doesnt need to go.Does he need to go?He dares to say.He does not dare(to)say.Do you dare to jump into the water from here,If you dare,so dare I.33Used to与 would 用法对比1.表示过去的动作、状态,重在现在情况的对比,不一定要有时间状语.used to wouldI used to play cards a lot,but now I seldom play.只表示过去动作的重复,有明确的时间状语.I would go to see my grandfather on Sunday when I was in the middle school.2.表示过去的习惯,可互换.When we were very young,we used to/would go skating every winter.34