高三英语一轮语法突破ppt课件情态动词和虚拟语气

1、,第二部分 语法考点突破,第七讲情态动词和虚拟语气,一、情态动词的基本用法,(1)表示禁止(用于否定句)。,You mustnt park here！Its an emergency exit.,(2)表必要性，意为“必须”。,Shall I inform him of the change of the schedule right now? I am afraid you must，in case he comes late for the meeting.,(3)表示偏执，固执，意为“非得，偏要”。,If you must go，at least wait until the storm

2、 is over.,(1)表示“能力”。,No one can be compared with Yao Ming in playing basketball. Oh，you are really his big fan.,(2)表示惊讶,常用在否定句和疑问句中。,How could you do such a silly thing？,(3)表示礼貌地请求别人做某事，意为“能，可以”。,This dish is really delicious.Could you please say it in Chinese? Sure，we call it“doufu” What should I w

3、ear to the party? Well，it isnt very formal.You can wear whatever you like.,(4)cannot.too/enough表示“无论也不过分”; “越越好”。,You cant be too careful while driving.,(1)用于第一、第三人称疑问句中,表示说话人征求对方的意见和向对方请示。,Shall I go out for a walk after supper?,(2)用于第二、第三人称陈述句中，表示说话人给对方的命令、警告、允诺或威胁。,Will you read me a story，Mummy?

4、 OK.You shall have one if you go to bed as soon as possible.,(1)may和might表示 “许可”,“可能性”, “祝愿”等意义。,May I take this book out of the reading room? No，you mustnt.You read it in here.,(2)“may as well动词原形”意为“最好，倒不如”。,If you think the price of beef is too high，you may as well buy some pork.It depends on you

5、.,(1)表示意志、意愿和决心。,I have told him again and again to stop smoking，but he will not listen.,(2)will可以表示一种习惯的动作,有“总是”或 “总要”之意。,Every morning he will have a walk along this river.,(3)would可以表示过去的习惯动作，比used to正式，但没有“现已无此习惯”的含义。,When we worked in the same firm several years ago，we would often go to the cin

6、ema together.,二、情态动词表推测,must表示推测时只能用于肯定句中，意为“一定，必定”，表示十分肯定的语气(在疑问句中或否定句中要用can/could)。,Its the office！So you must know eating is not allowed here. Oh，sorry.,(1)can用于肯定句中表示客观的可能性，意为“有时会”； (2)用于疑问句中可以表示推测，意为“可能”，有时表示一种惊讶的语气； (3)用于否定句中也可以表示推测，cant意为“不可能”，语气很强烈。,It is usually warm in my hometown in March

7、,but it can be rather cold sometimes. Mr.Bush is on time for everything.How can it be that he was late for the meeting? It cant be the postman at the door.Its only six oclock.,(1)may/might用于肯定句中可以用来表示不十分肯定的推测，意为 “有可能”； (2)用于否定句中也可以表示推测，may not意为“可能不”，表示一种不太确定的语气。,(2013高考北京卷)You neednt take an umbrel

8、la.It isnt going to rain. Well，I dont know.It might do.,should用来表示推测时意为“应该”，即含有“按道理来说应当如 此”的意思。,There shouldnt be any difficulty about passing the road test since you have practiced a lot in the driving school.,三、情态动词have done,表示对过去已经发生的行为进行推测,意为“一定做了某事”。,(2013高考辽宁卷) Harry is feeling uncomfortable.H

9、e must have drunk too much at the party last night.,表示对过去已发生行为的推测,意为“也许/或许已经(没有) ”。一般用于肯定句或否定句中。,Sorry，Im late.I might have turned off the alarm clock and gone back to sleep again.,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。(can换成could时语气较委婉),I cant find him anywhere.Where can he have gone? The boy cant have fi

10、nished reading the book so soon because it is difficult even to an adult.,本来能够而没有做,(2012高考北京卷)We could have faced the difficulty together，but why didnt you tell me？,表示本来可能,但实际上没有发生的事情。,You should not swim in that sea.You might have been eaten by a shark.,(1)用于肯定句时，表示本该做某事而实际上未做； (2)用于否定句时，则表示不该做的事反而

11、做了。,You shouldnt have done it so carelessly. You ought to have returned the book earlier.,表示做了本来不必去做的事，“没必要做而做了”。 注意didnt need to do表示“没必要做而实际上也没有做某事”。,You neednt have brought the book because Tom has one here. I didnt need to buy the dictionary.I had a copy at home.,一、if条件从句中的虚拟语气,与现在事实相反,从句谓语动词：过去

12、式(be用were) 主句谓语动词：should/would/ could/might动词原形,(2012高考湖南卷)Sorry, I am too busy now. If I had time, I would certainly go for an outing with you. 很抱歉，我现在非常忙。若我有时间，我将一定与你外出郊游。,与过去事实相反,从句谓语动词：had过去分词 主句谓语动词：should/would/could/mighthave过去分词,(2012高考山东卷)If we hadnt made adequate preparations，the conferenc

13、e wouldnt have been so successful.如果我们没有充足地准备，大会将不会如此地成功。,与将来事实相反,从句谓语动词：过去式/were不定式/should动词原形 主句谓语动词：should/would/could/might动词原形,(2012高考安徽卷)Grace doesnt want to move to New York because she thinks if she were to live there, she wouldnt be able to see her parents very often. Grace不想搬到纽约，因为她想如果要是住那

14、里，她将不可能经常地见到她的父母。,如果在表示虚拟语气的条件句中含有were，had或should，可将if省略,然后将were,had或should移至主语之前。,Had we made a great effort we might have succeeded.(If we had made a great effort.)要是我们付出巨大的努力,也许我们已经成功了。,有时条件句的动作与主句动作发生的时间不一致，这时动词的形式应根据它们表示的时间加以调整。,If it had rained last night,it would be very cool today.如果昨晚下雨了，今天

15、将会很凉爽。,二、含蓄条件句的虚拟语气 有时假设的情况并不以条件从句表示，而是由otherwise，but,or，without，but for等来引导。 I would have come sooner but I didnt know that they were waiting for me. 我本该早一些到，但我不知道他们在等我。 I couldnt have gone through that bitter period without your generous help. 假如当时没有您慷慨相助，我就不会度过那段艰难的时期。,三、虚拟语气在名词性从句中的应用,demand，sug

16、gest，order，insist后接的从句中动词为“(should)动词原形”。,Teachers recommend parents not allow their children under 12 to ride bicycles to school for safety.,wish后的从句中的谓语可用一般过去时、过去完成时和should/would动词原形,它们分别表示与现在、过去和将来情况相反。,How much of the foreign experts speech have you understood? Next to nothing.I wish I had worke

17、d harder at English.,在“It is necessary/important /strange/suggested/demanded/ordered/requestedthat从句”中，从句中的谓语动词用should动词原形。,It is strange that such a person should be our friend.,在suggestion,proposal,order, plan,idea,request,advice等名词后的表语从句和同位语从句中要用虚拟语气,其构成是“should动词原形”, should可以省略,My idea is that we (should) think it over before accepting it. We all agreed to his suggestion that we (should) go to Dalian for a visit.,四、其他句型中的虚拟语气,It is (high) time (that).句型中谓语动词用一般过去时或should动词原形。,Its high time that we devoted ourselves to environmental protection and ecological improvement.,would rather所接的从