1、modal verbmodal verbGrammar定义定义情态动词是一种本身有一定的词义情态动词是一种本身有一定的词义,但要但要与动词原形及其被动语态一起使用，给谓与动词原形及其被动语态一起使用，给谓语动词增添情态色彩，表示说话人对有关语动词增添情态色彩，表示说话人对有关行为或事物的态度和看法，认为其可能、行为或事物的态度和看法，认为其可能、应该或必要等。应该或必要等。情态动词后面加动词原形。情态动词后面加动词原形。注意注意分类：分类：情态动词有四类：情态动词有四类：只做情态动词：只做情态动词：must,can(could),may(might),ought to可做情态动词又可做实义动词
2、：可做情态动词又可做实义动词：need,dare可做情态动词又可做助动词：可做情态动词又可做助动词：shall(should),will(would)具有情态动词特征：具有情态动词特征：have(had,has)to,used to(一一)can,could的用法的用法考点一、情态动词的基本用法考点一、情态动词的基本用法1.表示体力或脑力表示体力或脑力(知识、技能知识、技能)所产生的所产生的能力能力。His mother can/could speak French.Man can/could not live without air.2.表示客观的表示客观的可能性可能性。Could you
3、wait a few days for the money?Could you be here at eight oclock tomorrow morning?3.表示表示请求请求,建议建议,用用could 比比 can语气更委婉语气更委婉(回答用原形回答用原形)。4.表示表示允许、许可允许、许可，用，用could 比比 can更委婉客气。更委婉客气。Could/Can I borrow your reference books?You can smoke in the entrance hall.1.My English-Chinese dictionary has disappeared
4、.Who _ have taken it?A.should B.must C.could D.would【2012全国卷全国卷II】Im going to Europe on vacation together with John if I _ find the money.A.canB.mightC.wouldD.needMay I ask you a question?Might I close the window?1.表示表示允许、请求允许、请求。Might I？比比 May I？语气更委婉和有礼貌。语气更委婉和有礼貌。(二二)may,might的用法的用法2.表示表示可能性可能性，表
5、示，表示“或许，大概或许，大概”。用于肯定句或否定句。用于肯定句或否定句 中，用中，用might 比比 may语气更加不肯定。语气更加不肯定。He might come tomorrow.He may be very busy these days.May you succeed!May the friendship between us last forever!3.表示表示祝愿祝愿。(不用不用might)采用部分倒装语序：采用部分倒装语序：may主语动词原形主语动词原形1.(2010四川四川)-_ I take the book out?-Im afraid not.A.Will B.Ma
6、y C.Must D.Need2.（2008四川非延考区）四川非延考区）Although this _ sound like a simple task,great care is needed.A.must B.may C.shall D.shouldShall I turn off the light?(三三)shall,should,ought to的用法的用法1.shall用于用于第一、第三人称第一、第三人称作主语的作主语的疑问句疑问句中，中，表示征求对方的意见。表示征求对方的意见。You shall go with me.You shall not leave your post.2
7、.shall用于用于第二、第三人称第二、第三人称作主语的作主语的陈述句陈述句中，表示中，表示 说话人的决心、意志、许诺、命令、警告、威胁等。说话人的决心、意志、许诺、命令、警告、威胁等。You should keep your promise.1.should意为意为“应该应该”，表义务、责任表义务、责任，也可表示劝告、，也可表示劝告、建议。建议。Mother should be back by now.2.should表示按常规、常理表示按常规、常理推测推测，意为，意为“可能可能”或或“应该应该”。Why should you be so late?How should I know?我怎会
8、知道！我怎会知道！(意为：我不知道。意为：我不知道。)3.Why/How should结构表示说话人对某事不能理解，结构表示说话人对某事不能理解，感到意外、惊异等意思，意为感到意外、惊异等意思，意为“竟会竟会”。You ought to finish your work before you go home.ought to表示责任和义务表示责任和义务“应该应该”，语气比，语气比 should强；还可表推测。例如：强；还可表推测。例如：You have practiced for a long time.There ought to be no difficulty for you.1.The
9、 room is so dirty._ we clean it?Of course.(2003北京春北京春)A.Will B.Shall C.Would D.Do【2012辽宁辽宁】2.One of our rules is that every student _ wear school uniform while at school.A.might B.could C.shall D.will3.If you listen to me,you _ have some candies,dear.A.shall B.might C.will D.would-Shall I go and buy
10、 more fruits for the party?-No,I have already bought 3 baskets.That _ be enough.A.can B.should C.may D.might（2009天津）天津）this printer is of good quality.If it _ break down within the first year,we would repair it at our expense.A.would B.should C.could D.might-Look,there is a lot of smoke coming from
11、the house.-It _be a fire,most probably.A.must B.ought to C.can D.mayI will do my best to help you.He said that they would help us.(四四)will,would，used to的用法的用法1.用于用于各种人称各种人称，表示意志或决心。，表示意志或决心。will指现在，指现在，would则指过去。则指过去。2.用于用于第二人称第二人称的的疑问句疑问句中表示有礼貌的询问和请求，中表示有礼貌的询问和请求，would 比比 will更委婉。更委婉。Would you teac
12、h me how to drive a car?Will you please give him a message when you see himFish will die without water.He would come to see me on Sunday when he was in Beijing.3.表示表示习惯性、经常性、倾向性习惯性、经常性、倾向性，意为，意为“总是总是”，“惯于惯于”。will指现在，指现在，would是指过去。是指过去。That will be the man you want to see.Perhaps she would be willing
13、 to meet us.4.表示说话人的表示说话人的推测推测，意为，意为“大概，也许大概，也许”。would 的的 肯定性不如肯定性不如will强，语气比较弱。强，语气比较弱。would 与与used to 的区别：的区别：We would sit in the yard every evening and listen to his story.We used to sit in the yard every evening and listen to his story.There used to be a park here.used to表示过去的某种习惯，现在已经没那样的习惯了；表示
14、过去的某种习惯，现在已经没那样的习惯了；would 表示过去有某种习惯，现在可能还有。表示过去有某种习惯，现在可能还有。表示过去的状态，只能用表示过去的状态，只能用used to，不能用，不能用would。【2012福建福建】31.We lost our way in that small village,otherwise we _ more places of interest yesterday.A.visited B.had visited C.would visit D.would have visited7.Mike promised his doctor he _ not dri
15、nk,and he has never drunk ever since.A.might B.should C.could D.wouldI _get up late,but now I have got used to getting up very early.used toEverybody must obey the rules.You mustnt speak like that to your mother.(五五)must，have to的用法的用法1.must 表示表示“必须必须”。强调。强调主观主观看法，只有现在时形式，看法，只有现在时形式，否定式是否定式是must not(
16、mustnt)，表示，表示“禁止禁止”，“不不准准”。How old are you,madam?If you must know,Im twice my sons age.2.must有有“偏要、硬要偏要、硬要”之意。之意。As he had broken his leg,he had to lie in bed.have to表示表示“必须，不得不必须，不得不”，着重强调，着重强调客观客观需要，需要，能用于更多时态能用于更多时态(过去式和将来式过去式和将来式)。(六六)need的用法的用法You neednt water the tomato plants now.Need he come
17、 now?Yes,he must./No,he neednt./he doesnt have to.1.need作情态动词表示作情态动词表示“需要需要”，“必要必要”。通常用于。通常用于 否定句、疑问句、条件句中，且只有现在时，其他时态否定句、疑问句、条件句中，且只有现在时，其他时态 用用“have to”的相应形式代替。的相应形式代替。The house needs repairing.The house needs to be repaired.房子需要修理。房子需要修理。2.need还可以用作还可以用作行为动词行为动词，其变化和一般的动词相同。，其变化和一般的动词相同。若主语为动作承受者
18、时用动词主动形式表示被动意义或若主语为动作承受者时用动词主动形式表示被动意义或 用不定式的被动形式。用不定式的被动形式。1.-_ you interrupt now?Cant you see Im on the phone?(2012重庆重庆)-Sorry Sir,but its urgent.A.Can B.Should C.Must D.Would2.The new law states that people _ drive after drinking alcohol.(2012上海上海)A.wouldnt B.neednt C.wont D.mustnt3.-Shall I info
19、rm him of the change of the schedule right now?(2011福建福建)-I am afraid you _,in case he comes late for the meeting.A.will B.must C.may D.can.-Lucy doesnt mind lending you her dictionary.-She _.Ive already borrowed one.A.cant B.mustnt C.needntD.shouldnt【2012全国全国】30.I _use a clock to wake me up because
20、 at six oclock each morning the train comes by my house.A.couldnt B.mustntC.shouldnt D.needntShe dare not go there.How dare she do such a thing?(七七)dare的用法的用法1.dare作情态动词表示作情态动词表示“敢于敢于”用于否定句、疑问句和用于否定句、疑问句和 条件句中。条件句中。2.惯用短语惯用短语“I dare say”意为意为“我想，大概我想，大概”。I dare say he is right.Do you dare to jump int
21、o the ocean?I dont dare(to)ask her.3.dare还可以用作行为动词，其变化与一般动词相同。还可以用作行为动词，其变化与一般动词相同。(在否定句中时，在否定句中时，dare后的后的“to动词原形动词原形”可以省略可以省略to)。考点二：考点二：can/may/must/need 问句的回答方式问句的回答方式Can/Could you do sth.Yes,I/we/can/couldNo,I wecant/couldntMay I do sth.?Yes,No,you Must I/we do sth.?Yes,No you Need I do sth.?Yes
22、,No,you 疑问句式肯定句式否定答式you may.mustnt/may not.you mustneednt/dont have to.you must.neednt/dont have to.1.-Will you stay for lunch?-Sorry,_.My brother is coming to see me.A.I mustnt B.I cant C.I neednt D.I wont2.-May I pick a flower in the garden?-_.A.No,you neednt B.Not,please.C.No,you mustnt D.No,you
23、wontB B C C 考点三：固定搭配中的情态动词：考点三：固定搭配中的情态动词：cannot/couldnt but do sth.不得不；只好不得不；只好“cannot/(cant)too/over/enough”。表示。表示 “无论怎么无论怎么也不也不(过分过分)”，用来加强语气，用来加强语气I couldnt but choose to wait.May/(might)as well动词原形：不妨做动词原形：不妨做，最好，最好Now that they were all here,she might as well speak her mindYou cannot be too ca
24、reful.May/might well 很可能很可能-His appearance has changed so much that you may well not recognize him.1.I _ thank you too much for all you help to my son while we were away from home.A.wont B.cant C.can D.will2.Liza _ well not want to go on the trip-she hates traveling.A.will B.can C.must D.may考点四：情态动词
25、表推测考点四：情态动词表推测情态动词情态动词 can,could,may,might,must表推测的用表推测的用法：法：情态动词中的情态动词中的can,could,may,might,must都表推测。都表推测。其中其中must的可能性最大，的可能性最大，can/could次之，次之，may/might最小。最小。(可能是可能是Kate。)(不可能是不可能是MarryMarry。)Someone is knocking at the door.Who is it?(一定是一定是Tom。)It must be Tom.It/may/might be Kate.It cant be Marry
26、表猜测，用于肯定句中，表猜测，用于肯定句中，“一定一定”_ 表猜测，常用于否定、疑问句中表猜测，常用于否定、疑问句中_ 表猜测，常用于肯定、否定句中表猜测，常用于肯定、否定句中must_cant_couldnt_May_ might not_表猜测的情态动词表猜测的情态动词 must can/could may/might一定一定不可能不可能可能不可能不不可能不可能可能可能他肯定知道我的地址。他肯定知道我的地址。他肯定不知道我的地址。他肯定不知道我的地址。他知道我的地址吗？他知道我的地址吗？1.must表推测只能用于肯定句。表推测只能用于肯定句。如表示如表示“一定不、肯定不一定不、肯定不”的意
27、思时，应用的意思时，应用cant,如询如询问某种可能时，应用问某种可能时，应用can。He must know my address.He cant know my address.Can he know my address?（一定）（一定）（一定不）（一定不）（询问可能性）（询问可能性）2.must表示推测时，可以推测现在表示推测时，可以推测现在/正在发生的动作正在发生的动作/过去发生的动作。过去发生的动作。他一定有辆小汽车。他一定有辆小汽车。He must have a car now.他一定正在教室里做练习。他一定正在教室里做练习。He must be doing his exerci
28、ses in the classroom.他一定已完成了工作。他一定已完成了工作。He must have finished the work.注：注：must表示推测时表示推测时很少用于将来的情况很少用于将来的情况。一般不用一般不用He must come tomorrow.可用可用Its certain/Im sure that he will come tomorrow.He must be a worker,_?（现在）（现在）You must have learned English for many years,_?（完成时）（完成时）比较：比较：It must have rain
29、ed last night,_?（过去）（过去）He must have arrived by yesterday morning,_?在反意疑问句中，当附属部分含有表示推测意义的在反意疑问句中，当附属部分含有表示推测意义的must时，疑问部分的助动词应与时，疑问部分的助动词应与must后面的动词后面的动词在非推测情况下的用法保持一致。在非推测情况下的用法保持一致。isnt hehavent youdidnt ithadnt he2.can/could的用法的用法（1）can表示推测表示推测“可能性可能性”时，往往用于否定句或疑时，往往用于否定句或疑问句。问句。cant“一定不一定不”，can
30、在疑问句中意思是在疑问句中意思是“会、会、可能可能”。=It is impossible that he is at home.他一定不在家。他一定不在家。（2）can/cant+have done，表示对过去发生的动作，表示对过去发生的动作进行推测。进行推测。他不可能去了上海，我刚才还看见他。他不可能去了上海，我刚才还看见他。天晚了，她可能去哪儿了呢？天晚了，她可能去哪儿了呢？He cant be at home.He cant have gone to Shanghai for I saw him a minute ago.Its so late.Where can she have go
31、ne?3.may和和might的用法的用法（1）may,might表示推测表示推测“可能性可能性”时，意思是时，意思是“可可能能”、“也许也许”他可能是个美国人。他可能是个美国人。注：注：might不表示过去时态，只是语气上比不表示过去时态，只是语气上比may更委婉，更委婉，表示的可能性更小。表示的可能性更小。（2）may,might表推测时，可以用于否定句，意思是表推测时，可以用于否定句，意思是“可能不、也许不可能不、也许不”，但，但不用于疑问句不用于疑问句。他也许不在家。他也许不在家。He may/might be American.=It is possible that he is A
32、merican.He may/might not be at home.（3）may,might可以推测现在正在发生的动作或过去可以推测现在正在发生的动作或过去发生的动作。发生的动作。这个男孩可能没在家看电视这个男孩可能没在家看电视这些学生以前可能看过这部电影。这些学生以前可能看过这部电影。The boy may/might not be watching TV at home.These students may/might have seen the film before.（过去）（过去）4.What_ it be?-It_ be a mail box,for it is moving.
33、It_ be a car.A.can;cant;must B.can;can;mustC.can;mustnt;must D.must;mustnt;can5.Look,someone is coming.Guess_.-Jack.Hes always on time.A.who can it be B.who he mayC.who he can be D.who it can be情态动词情态动词+have+done”表表“本来应该本来应该”使用情况分使用情况分析析一、一、should have done过去本来应该（而实际上并没有过去本来应该（而实际上并没有)should not hav
34、e done 本不应该本不应该 而实际上却已经而实际上却已经”我们昨晚本应学习的，但我们却去看音乐会了。（实际上我们昨晚本应学习的，但我们却去看音乐会了。（实际上没有学习）没有学习）We should have studied last night,but we went to the concert instead.二、二、could have done它表示它表示“过去本来能够过去本来能够”实际上没能做实际上没能做。我本来能用我本来能用12秒钟完秒钟完100米的米的.如果你当时能如期完成那任务的话，你可能已提升了如果你当时能如期完成那任务的话，你可能已提升了I could have run
35、 100 meters in 12 seconds.If you could have finished the task in time，you could have been promoted.三、三、need not have done它表示过去已做的事，事实上没有必要。它表示过去已做的事，事实上没有必要。我本来不必要那么早起床的我本来不必要那么早起床的我本来不必要等一个小时的火车。我本来不必要等一个小时的火车。I need not have got up so early.I need not have waited for the train for an hour.四、四、woul
36、d have done 用在虚拟语气中用在虚拟语气中 表示与过去事实相反之假设的结果，常与表示与过去事实相反之假设的结果，常与if 的条件句连的条件句连用用。1、I would have helped you if I had known of your difficulties.要是我当时知道你们的窘境，我就会帮助你要是我当时知道你们的窘境，我就会帮助你了（而实际上没有帮助你）了（而实际上没有帮助你）2、If it hadnt rained yesterday,we would have gone out for a walk.假如昨天没下雨，我们就去散步了。假如昨天没下雨，我们就去散步了。
37、（实际上没有去）。（实际上没有去）。Practice1.Mr White _ at 8:30 for the meeting,but he didnt turn up.A.should have arrived B.should arrive C.should have had arrived D.should be arriving2.If he had been here yesterday,he _ this pop star.A.would meet B.would have metC.met D.must have met3.It is hard for me to imagine what I would be doing today if I_ in love at the age of seven with the Melinda Cox Library in my hometown.A.wouldnt have fallen B.had not fallenC.should fall D.were to fall
