《2020版高考英语新增分大一轮复习语法专题全辑专题七情态动词和虚拟语气讲义牛津译林版》由会员分享，可在线阅读，更多相关《2020版高考英语新增分大一轮复习语法专题全辑专题七情态动词和虚拟语气讲义牛津译林版（23页珍藏版）》请在金锄头文库上搜索。
1、专题七 情态动词和虚拟语气情态动词的核心考点1.can，be able to 和could(1)can和be able to都表示能力，意思上没多大区别。但can只有现在和过去时，而be able to则有更多的形式。但当成功地完成某一具体动作时，通常不用could而用was/were able to来表示。这时was/were able to 相当于managed to，表示经过一番努力，终于能够完成某事。Her mother can speak French.The wounded man was still able to get to the village and was saved
2、 by the villagers in the end.(2)表示猜测“可能”，一般用于疑问句和否定句。Can the news be true?It cant be true.Someone is knocking at the door.Who could it be?(3)can可以表示理论上的可能性，指常有的行为或情形，意为“有时会”。Anybody can make mistakes.(4)表示请求、允许(表请求时，口语中常用could代替can使语气更委婉，回答时用can)。Can I go now?Could I come to see you tomorrow?Yes，you
3、 can.(否定答语可用No，Im afraid not.)(5)表示惊异、怀疑、不相信的态度(主要用于否定句、疑问句或感叹句中)。How can that be true？I cant believe my eyes and ears.How could you be so careless?(6)can的特殊用法。can but只有；cant but不得不；cant.too再也不为过，越越好I can but wait.I cant but wait.You cant be too patient to the customers.题组训练1用can，could，be able to的适当
4、形式填空1.Though the building was on fire，they wereableto go out safely.2.It cant be the postman at the door.Its only six oclock.3.Hows your new babysitter?We could not ask for a better one.All our kids love her so much.4.The police still havent found the lost child，but theyre doing all they can.5.You c
5、ant be too careful when driving.2.may和might的用法(1)表示允许、请求，might比may的语言更委婉一些。May I watch TV now?Yes，you may.(Yes，please.)No，you mustnt.(No，youd better not.)(2)表示可能性时，might比may的可能性小，may表示的可能性比can小(主要用于陈述句、肯定或否定句，疑问句用can代替)。The story may not be true.(3)表示祝愿(不用might)May you succeed!(4)may/might as well最好
6、还是，不妨You might as well do it now.(5)may/might well很可能He may well be late for class.题组训练2用may，might的适当形式填空1.I dont really like James.Why did you invite him?Dont worry.He might/may not come.He said he wasnt certain what his plans were.2.I left my handbag on the train，but luckily someone gave it to a r
7、ailway official.How unbelievable to get it back! I mean，someone might have stolen it.3.As a student，you might/may as well make good use of your time.4.You may go to school either by bike or by bus.5.May she rest in peace.3.must，have to和ought to的用法(1)must表示“必须，应该，一定要”。强调主观看法，只有现在时形式，否定式是must not(must
8、nt)。must开头的问句，其否定回答要用neednt或dont have to代替。(2)must表示必然的结果。All men must die.(3)must还可表示主语固执、偏要做他人不希望做的事。It cant help；he must do that.(4)have to着重客观需要，能用于更多时态(过去时或将来时)。He will have to be there before ten.(5)ought to表示义务和责任，“应该”，比should语气要强。You ought to take care of yourself.4.need和dare的用法(1)need表示“需要，
9、必要”，只能用于否定句和疑问句。在肯定句中，常用must和have to代替。(2)dare表示“敢”，通常用于否定句、疑问句和条件状语从句中。Dare you go home alone at eleven in the evening?(3)need和dare的特殊用法need表“需要”时，可用want，require代替。The desk needs to be repaired./The desk needs repairing.dare作实义动词时，在肯定句中要接to，在疑问句和否定句中to可省去。He dares to catch a snake.I do not dare (to
10、) complain.Do you dare (to) swim in the river?题组训练3同义句改写1.He darent go out at night.He doesnt dare to go out at night.2.The flowers need watering.The flowers need to be watered.5.will和would的用法(1)will表示请求、建议，常用于第二人称。Will you please go with me?表示意愿、决定、允许。I will never do that again.表示习惯性动作或某种倾向，“总是，惯于”
11、，通常用于第三人称。Rosa will always be late for school.(2)would表示请求、建议，比will委婉，指现在时间，多用于第二人称。Would you like a cup of tea? 表示过去习惯性动作或某种倾向。We would play badminton on Sundays.6.shall和should的用法(1)shall用于第一、三人称，在问句中表示征求对方意见或请求。Shall I come in?用于第二、三人称的陈述句中，表示命令或威胁。You shall do as your father says.(2)should表示责任、义务
12、，意为“应该”。表示惊讶语气，意为“竟然”。You should wear slippers in class.用于条件句，表示“假如，万一”，省去if，should可提至句首。Should you be late，apologize to the teacher.7.情态动词表示推测或判断的用法下表即是表示推测的情态动词使用的场合：情态动词对现在和未来的推测对过去的推测使用场合mustmustdomust have done肯定句may/mightmay/mightdomay/might have done肯定句、否定句can/couldcan/could docan/could have
13、done否定句、疑问句(could可用于肯定句)should用来表示一种估计的情况“按理会/估计会”should doshould have done肯定句、否定句、疑问句情态动词have done的用法：(1)should have done表示“本来应该做某事而实际上未做”，而shouldnt have done则表示“本不应该做某事而实际上做了”。You should have told me about it earlier.You shouldnt have said such words to your parents.(2)ought to have done也表示“本应该”，而
14、ought not to have done则意为“本不应该”。You ought to have told me about it earlier.You ought not to have said such words to your parents.(3)neednt have done表示“本无必要做某事而实际上做了”。You neednt have walked so quickly since time was enough.(4)could have done表示“本来有可能而事实上未做到”。I could have come on time，but my car broke
15、down on the way.(5)may/might have done表示“过去可能发生过某事”或“本来应该或可以做某事(实际上没做)”。You might have given him more help，but you were so busy.题组训练41.I couldhavehelpedyou(我本来可以帮助你的)，but I was too busy then.2.Its Sunday.He canthavegonetoschool(不可能上学去了).3.You know the story very well.You may/mighthavereadit(可能读过) before.4.You musthavegonetobedlate(一定是睡得很晚) last night.Your eyes are red.5.I should/oughttohavedonemyhomew
