高中英語情態(tài)動詞和虛擬語氣課件

1、高中英語情態(tài)動詞和虛擬語氣最新考點(diǎn)一：情態(tài)動詞一、can， could與be able to1.表示能力(體力、知識、技能)。例：Can you lift this heavy box?(體力)Mary can speak three languages.(知識)Can you skate?(技能) 此時可用be able to代替。can只有一般現(xiàn)在時和一般過去式； 而be able to則有更多的時態(tài)。Ill not be able to come this afternoon.當(dāng)表示“經(jīng)過努力才得以做成功某事”時應(yīng)用be able to， 不能用can。He was able to go

2、 to the party yesterday evening inspite of the heavy rain.知識精講2.表示請求和允許。例：-Can I go now?-Yes， you can./No， you cant.此時可與may互換。在疑問句中還可用could， might代替， 不是過去式， 只是語氣更委婉， 不能用于肯定句和答語中。例：-Could I come to see you tomorrow?-Yes， you can.(No， Im afraid not.)知識精講3.表示客觀可能性(客觀原因形成的能力)。例：Theyve changed the timeta

3、ble， so we can go by bus instead. This hall can hold 500 people at least.知識精講4.表示推測(驚訝、懷疑、不相信的態(tài)度)，用于疑問句、否定句和感嘆句中。例：Can this be true?This cant be done by him.How can this be true?知識精講【典型例題】1.(單項(xiàng)填空) In todays information age， the loss of data_cause serious problems for a company.2.(單項(xiàng)填空) Samuel， the t

4、allest boy in our class,_easily reach the books on the top shelf.知識精講二、may， might1.表示請求和允許。might比may語氣更委婉， 而不是過去式。否定回答時可用cant或must n*t， 表示“不可以， 禁止”。例：-Might/May I smoke in this room?-No， you mustnt.-May/Might I take this book out of the room?-Yes， you can.(No， you cant/mustnt.)知識精講2.用于祈使句，表示祝愿。例：May

5、 you succeed!知識精講典例剖析】You _ feel all the training a waste of time， but Im a hundred percent sure later youll be grateful you did it.知識精講三、must，have to1.表示必須、必要。例：You must come in time.在回答引出的問句時， 如果是否定的， 不能用mustnt(禁止， 不準(zhǔn)) ， 而用neednt， dont have to(不必)。例：-Must we hand in our exercise books today?-Yes，

6、you must/No， you dont have to/you neednt.知識精講2.must是說話人的主觀看法， 而have to則強(qiáng)調(diào)客觀需要。must只有一般現(xiàn)在時， have to有更多的時態(tài)形式。例：I really must go now.I had to work when I was your age.知識精講 3.must表示推測、可能性(只用于肯定的陳述句) 。例：Youre Toms good friend， so you must know what he likes best.Your mother must be waiting for you now.知識

7、精講 【誤區(qū)警示】1.must開頭的疑問句， 其否定回答通常用dont have to或need nt。而不用must n。例：-Must I finish my homework first?我必須先完成作業(yè)嗎?-No， you dont have to/need n*t.不，你不必。知識精講 【誤區(qū)警示】2.can和must在表推測時， can一般用于否定句中， 而must常用于肯定句中。例：It can not be LiLe i.那個人不可能是李磊。It must be LiLe i.那個人肯定是李磊。知識精講 【典例剖析】1.-Cant you stay a little longe

8、r?-Its getting late， I really_go now， my daughter is home alone.2.You_be careful with the camera. It costs!知識精講四、dare， need 1.dare作情態(tài)動詞用時， 常用于疑問句、否定句和條件從句中， 過去式形式為dared，例：How dare you say Im unfair?He darent speak English before such a crowd， dare he?If we dared not go there that day， we couldnt get

9、 the beautiful flowers.知識精講 2.need作情態(tài)動詞用時， 常用于疑問句、否定句。在肯定句中一般用must， have to， ought to， should代替。例：You neednt come so early.-Need I finish the work today?-Yes， you must/No， you neednt.注意：dare和need作實(shí)義動詞用時， 有人稱、時態(tài)和數(shù)的變化。在肯定句中， dare后面常接帶to的不定式。在疑問句和否定句中， dare后面可接帶to或不帶to的不定式。而need后面只能接帶to的不定式。例：ld are to

10、 swim across this river.He doesnt dare(to) answer.He needs to finish his homework today.知識精講五、shall， should 1.shall用于第一人稱， 征求對方的意見。例：What shall we do this evening?知識精講 2.shall用于第二、三人稱， 表示說話人給對方的命令、警告、允諾或威脅。例：You shall fail if you dont work hard.(警告)He shall have the book when I finish it.(允諾)He shal

11、l be punished.(威脅)知識精講3.should表示義務(wù)、職責(zé)等， 意為“應(yīng)該”。例：You should be strict with yourself as an officer.作為一名官員，你應(yīng)該嚴(yán)格要求自己。知識精講六、will， would1.表示請求、建議等， would更委婉。例：Wil/Would you pass me the ball， please?知識精講2.表示意志、愿望和決心。例：I wll never do that again.They asked him if he would goabroad.知識精講3.would表示過去反復(fù)發(fā)生的動作或某種

12、傾向。would表示過去習(xí)慣時比used to正式， 且沒有“現(xiàn)已無此習(xí)慣”的含義。例：During the vacation， he would visit me every other day.The wound would not heal.知識精講【真題剖析】(短文改錯) As the kid， I loved to watch cartoons， but no matter how many times I asked to watching them， my parents would not to let me.知識精講七、should， ought to1.shoud， oug

13、ht to表示“應(yīng)該”， ought to表示義務(wù)或責(zé)任， 比should語氣重。例：I should help her because she is in trouble.You ought to take care of the baby.知識精講2.表示勸告、建議和命令。should， ought to可通用， 但在疑問句中常用should。例：You should/ought to goto class right away.Should I open the window?知識精講3.表示推測should， ought to(客觀推測) ， must(主觀推測) 。例：He must

14、 be home by now.(斷定他已到家)He ought to/should be home by now.(不太肯定)This is where th coil must be.(直爽)This is where the oil ought to/should be.(含蓄)知識精講考點(diǎn)二：情態(tài)動詞+have done知識精講 1.must have done表示對過去事情的肯定推測， 譯成“一定做過某事”， 該結(jié)構(gòu)只用于肯定句。例：It must have rained last night， for the ground is wet昨晚一定下雨了，因?yàn)榈孛孢€是濕的。You mu

15、st have been mad to speak to the servant.你和仆人說話，一定是發(fā)瘋了。知識精講 2.cant have done表示對過去事情的否定推測， 譯成“不可能做過某事”，例：Mr Smith canth avc gone to Beijing， for I saw him in the library just now.史密斯先生不可能去北京了，我剛才還在圖書館見過他。Mary cant have stolen your money.She has gone home.瑪麗不可能偷你的錢，她回家去了。知識精講3.can have done表示對過去行為的懷疑，

16、 用于疑問句， 譯成“可能做過嗎?”例：There is no light in the room.Can they have gone out?屋里沒有燈，他們可能出去了嗎?There is nowhere to fnd them.Where can they have gone?到處找不到他們，他們可能到什么地方去呢?知識精講4.could have done是虛擬語氣， 表示對過去事情的假設(shè)， 意思是本來能夠做某事而沒有做。例：He could have passed the exam， but he was too car c less，本來他能夠通過考試，但是他太粗心。知識精講5.m

17、ay have done表示對發(fā)生過的事情的推測， 意思是“可能已經(jīng)”或“也許已經(jīng)”， 用于肯定句中。例：-What has happened to George?喬治發(fā)生了什么事?-I dont know. He may have got lost.我不知道，他可能迷路了。知識精講6.might have done表示對過去事情的推測， might與may意思相同， 但可能性更小。多用于虛擬語氣結(jié)構(gòu)中。例：She might have achieved greater progress， if you had given her more chances.如果你多給她點(diǎn)機(jī)會，她可能已經(jīng)取得了

18、更大的成績。知識精講7.would have done虛擬語氣， 表示對過去事情的假設(shè)， 意思是“本來會”例：I would have told you all about the boys story， but you didntask me.我本來會告訴你這個小男孩的故事，但是你沒有問我。知識精講8.should have done“本來應(yīng)該做某事， 而實(shí)際沒做”， 含有指責(zé)對方或自責(zé)的含義。例：Tom， you are too lazy.The work should have been fi ished yesterday.湯姆，你太懶惰了，這項(xiàng)工作本來應(yīng)該昨天就做完的。Look， T

19、om is crying.I should nt have been so harsh on him.看，湯姆哭了，我本不應(yīng)該對他如此嚴(yán)厲的。知識精講9.ought to have done表示過去應(yīng)該做而實(shí)際并沒有做，have done”用法基本一樣?！袄響?yīng)做”， 往往表示遺憾。與“should例：I ought to have gone home last Sunday.我理應(yīng)上星期日回家。You ought not to have given him more help.你不應(yīng)該幫助他那么多。知識精講10.need have done表示本來需要做某事而實(shí)際沒有做。neednt have

20、 done則表示本來不需要做某事而實(shí)際做了。例：I neednt have bought so much wine-only five people came.我本來沒有必要買這么多酒，只來了五個人。He need have hurried to the station.In that case， he wouldnt have missed the train.他本來需要快點(diǎn)去車站的，那樣的話，他就不會誤了火車。知識精講【典例剖析】例：-Sorry， Mum! I failed the job interview again.-Oh， its too bad. You have made f

21、ull preparations.知識精講考點(diǎn)三：虛擬語氣一、虛擬語氣在條件句中的應(yīng)用包含條件從句的句子稱為條件句。條件句分為兩類：一類是真實(shí)條件句，一類是虛擬條件句。如果假設(shè)的情況很可能發(fā)生，就用真實(shí)條件句。例：If he has time， he will come，如果他有時間，他會來的。例：He wont succeed unless we plan well.他不會成功的，除非我們計(jì)劃好。知識精講如果假設(shè)的情況發(fā)生的可能性不大，則用虛擬條件句。虛擬條件句分為三種，見下表：例：If he had time now， he would/could/might go with you.要是

22、他現(xiàn)在有時間，他會和你一起去的。(與現(xiàn)在事實(shí)相反)例：If you had come a few minutes earlier， you would/could/might have met the famous singer.如果你早來幾分鐘，你就會見到那個著名歌手了。(與過去事實(shí)相反)例：If it were to snow this evening， they would not go out.如果今天晚上下雪，他們就不會出去。(與將來事實(shí)相反)知識精講二、幾種特殊的虛擬條件從句 1.省略if形式的虛擬語氣在if虛擬條件句中， 若省略if， 則將should， were， had前置，

23、 構(gòu)成主謂倒裝句式。例：Had I worked harder， I would have succeeded.如果我當(dāng)時努力學(xué)習(xí)的話，我就會成功的。Were she my daughter(Should she be my daughter) ， I wouldntallow her to study abroad.如果她是我的女兒的話，我就不讓她出國學(xué)習(xí)了。知識精講2.混合虛擬語氣若主句和從句所表示的時間不一致，就構(gòu)成了混合虛擬語氣或錯綜虛擬語氣，此時，主句和從句的時態(tài)形式根據(jù)實(shí)際的時間概念來定。例：If she had followed the doctorswords， she wou

24、ld feel better now.如果當(dāng)初她聽從了醫(yī)生的建議，現(xiàn)在就會好多了。知識精講3.含蓄虛擬語氣有時候假設(shè)的條件不是通過條件從句表達(dá)， 而是隱含在某些介詞短語中， 如without.， 連詞but for，otherwise， or等中。例：Without music(=If the rc were no music) ， the world would be dull世界若無音樂將會很枯燥。Im really very busy， other wisc I would certainly go there with you.(other wisc=if I were not so

25、busy)我真的是太忙了，不然我就會同你一道去了。知識精講三、虛擬語氣在賓語從句中的應(yīng)用1.動詞wish后的賓語從句。表示現(xiàn)在的情況，從句謂語用過去式；表示過去的情況，從句謂語用過去完成式；表示將來的情況， 從句謂語用“would/should/could/might+動詞原形。例：I wish I were ten years younger now.我希望我現(xiàn)在年輕十歲。I wish I had met him yesterday.我昨天能遇到他就好了。I wish I would be a scientist.我希望將來成為科學(xué)家。知識精講【課堂演練】(單項(xiàng)填空) There is a good social life in the village, and I wish I_a second chance to become more involved.知識精講 2.在表示請求、建議、命令、要求等動詞后的賓語從句中， 謂語用“should+動詞原形”， should可省略。常見的這類動詞有：suggest， recommend， insist， order， require， advise， demand， command， ask， request，propose等。例：He suggested that we(sho