高頻考點一情態(tài)動詞表能力高頻考點一情態(tài)動詞表能力 can/could一般表示主語本身所具有的能力,意為:能,會;而be able to一般表示通過努力能做到某事。典例典例1 (2015浙江,4)It was so noisy that we hear ourselves speak.答案couldnt解析句意:這里如此嘈雜以至于我們無法聽到自己說話。根據(jù)語境可知此處表達(dá)過去的能力故用couldnt。考點清單考點清單高頻考點二情態(tài)動詞表推測高頻考點二情態(tài)動詞表推測情態(tài)動詞表推測分為:對現(xiàn)在情況和過去情況的推測、對情況肯定的推測、否定的推測以及可能性的推測。對現(xiàn)在情況的肯定推測就用must,否定推測就用cant,可能性推測就用can/could,may/might。對過去情況的肯定推測就用must have done,否定推測就用cant have done,可能性推測就用can/could/may/might have done。做題時要判斷是哪一種推測,還要判斷出是對現(xiàn)在還是對過去情況的推測。典例典例2 (2015重慶,12)You be Carol.You havent changed a bit after all these years.答案must解析句意:你一定是卡蘿爾,這么多年過去了你一點也沒變。根據(jù)語境可知此處表示對現(xiàn)在情況的肯定推測,所以要用must(一定)。高頻考點三情態(tài)動詞表請求、許諾、允許高頻考點三情態(tài)動詞表請求、許諾、允許1.向?qū)Ψ教岢龌蛘髑笠庖姇r一般要用比較委婉的語氣,常用的句式有:Shall I/he/they.?Could I.?May I.?2.情態(tài)動詞shall用于第二、三人稱表示說話者命令、警告、許諾的語氣。表示按照規(guī)章制度、法律、條例規(guī)定應(yīng)該怎么做也要用shall。這是高考對shall的考查熱點。典例典例3 (2014北京,27) I have a word with you?It wont take long.答案Can/May解析句意:我能和你說句話嗎?不會花很長時間的。本題考查情態(tài)動詞的基本用法。can/may可以,表請求允許。高頻考點四情態(tài)動詞表必要性高頻考點四情態(tài)動詞表必要性must語氣最強(qiáng)烈,表示說話者堅決認(rèn)為必須做某事;need語氣要比must弱,表示說話者認(rèn)為有必要做某事;should在表示該含義時,表示在義務(wù)上應(yīng)該做某事。should還表示“竟然會,(將來)萬一”。典例典例4 (2015北京,29)Cant you stay a little longer?Its getting late.I really go now.My daughter is home alone.答案must解析 句意:難道你不能再多逗留一會兒嗎?時間不早了。我現(xiàn)在確實得走了。我的女兒獨自一人在家。根據(jù)對話內(nèi)容可知空格處表示“必要性”,故用must。情態(tài)動詞+have done意義must have done想必/準(zhǔn)是/一定做了否定式為cant/couldnt have donecould have done本來能夠做can/could have done過去可能會做cannot/could nothave done1.過去不可能做2.過去沒能夠做may/might have done也許/或許已經(jīng)做了,一般只用于肯定句或否定句中(在否定句中表示“可能不”),不用于疑問句。用might則表示語氣更加不肯定高頻考點五情態(tài)動詞高頻考點五情態(tài)動詞+have doneshould/ought tohave done本該做而實際上未做shouldnt/oughtnot to have done本不該做而做了neednt have done本來不必做而做了had better have done要是當(dāng)時做了就好了,用于事后的遺憾,含輕微的責(zé)備,其否定式had better not have done表達(dá)相反的含義would rather have done寧愿當(dāng)時做了,其否定式would rather not have done表達(dá)相反的含義,兩者都表示“后悔”之意would like/loveto have done過去愿意做但未做成典例典例5 (2015天津,7)I have worried before I came to the new school,for my classmates here are very friendly to me.答案neednt解析句意:在進(jìn)入這所新學(xué)校之前我本沒必要擔(dān)心,因為這里的同學(xué)對我很友好。根據(jù)語境可知此處表達(dá)“過去對某事?lián)倪^,但現(xiàn)在看來這種擔(dān)心沒有必要”,應(yīng)該用neednt have done。高頻考點六虛擬語氣高頻考點六虛擬語氣 虛擬語氣是用來表示與現(xiàn)在或過去的實際情況相反的假設(shè),近年來主要是考查上述兩點,而對將來可能情況的假設(shè)已很少涉及。注意下列幾種情況:1.表示與現(xiàn)在實際情況相反的假設(shè):條件從句謂語動詞應(yīng)該用一般過去時(be動詞用were),主句謂語動詞要用should/might/would/could+動詞原形。2.表示與過去實際情況相反的假設(shè):條件從句謂語動詞應(yīng)該用過去完成時,主句謂語動詞要用should/might/would/could have done。3.用其他形式來代替條件從句,常見的有:without,otherwise,but for等。4.一些特殊動詞后的that從句中謂語動詞要用(should+)動詞原形,常?？疾榘裺hould去掉的情況。與這些特殊動詞相關(guān)的名詞形式后的that引導(dǎo)的同位語從句的謂語動詞也符合這一原則。5.需要特別注意的幾個結(jié)構(gòu):wish句式,as if/though句式,would rather.,Its high time.等。典例典例6 (2015北京,34)If I (see)it with my own eyes,I wouldnt have be-lieved it.答案hadnt seen解析句意:如果不是我親眼看到,我是不會相信的。由主句謂語“wouldnt have believed”可知此處為與過去事實相反的假設(shè),故if從句謂語動詞應(yīng)為hadnt seen。知識清單一情態(tài)動詞的用法要點知識清單一情態(tài)動詞的用法要點一、表能力如:I am starving to death.I can eat two bowls of rice now.(現(xiàn)在的能力)我快餓死了,現(xiàn)在我能吃兩碗米飯。If you have a good sleep,you will be able to work out this problem.(將來的能力)canam/is/are able towill be able to:couldwas/ were able tocould have:表現(xiàn)在的能力表將來的能力表過去的能力過去分詞 表示過去有能力做但未做知識清單知識清單如果你好好睡一覺,你將能夠解出這道題。The fire spread through the hotel very quickly but everyone was able to get out.(過去有能力做并且成功地做了某事)盡管這場大火迅速蔓延到了整個賓館,但是每個人都逃了出去。I could have worked out the problem,but I was too nervous.(過去有能力做但未做)我本來可以解出這道題,但我太緊張了。1.可能性可分為客觀的可能性和具體事情實際發(fā)生的可能性兩種。所謂客觀的(理論的)可能性即并不涉及具體某事是否會發(fā)生,此種用法常?？梢哉f明人或事物的特征。情態(tài)動詞can可用于肯定句中表示客觀的(理論的)可能性,而表示具體事情實際發(fā)生的可能性時,can 一般不用于肯定句。如:Accidents can happen on such rainy days.在這樣的多雨天里可能會發(fā)生事故。(客觀的可能性)We may go to the cinema tonight,but we are not sure yet.今晚我們可能去看電影,但還沒確定。(實際可能性,不用can)2.表示具體事情實際發(fā)生的可能性:(1)表示具體事情實際發(fā)生的可能性的層次比較(見下表)二、表推測(可能性)詞形肯定式否定式疑問式must必定,必然/should按說應(yīng)該應(yīng)該不會/ought to按說應(yīng)該應(yīng)該不會/can/不可能有可能嗎?could微弱的可能不可能語氣比can弱may或許,也許,也未可知,也說不定可能不/might比may還弱比may not還弱/(2)表示具體事情實際發(fā)生的可能性時,may,must常用于肯定句,一般不用于否定句和疑問句(may not表示“可能不”);can 常用于否定句、疑問句或感嘆句中,表示疑惑、驚訝或不相信等意思;could既可用于肯定句又可用于否定句、疑問句中。如:This cant/couldnt be done by him.這不可能是他干的。(表不相信)This may not be done by him.這可能不是他干的。(表不確定)He could be on his way home now.他現(xiàn)在可能在回家的路上了。(could 不如may/might常用)Can this be done by him?這可能是他干的嗎?(表示疑惑、驚訝)Mr.Bush is on time for everything.How can it be that he was late for the opening ceremony?布什先生做一切事情都非常守時。開幕式他怎么可能會遲到呢?(表示疑惑、驚訝)I didnt hear the phone.I must have been asleep.我沒聽見電話鈴響。我一定是睡著了。(表肯定)Are you coming to Jeffs party?Im not sure.I might go to the concert instead.(表不確定)你要來杰夫的聚會嗎?我不確定。我可能要去音樂會。(3)could,might并不一定與過去的時間有關(guān),而表示可能性弱于它們相應(yīng)的現(xiàn)在時形式。如:This may/might be done by him.這件事有可能是他干的。(語氣依次遞減)(4)should表推測時,表示確定或可能有的未來或期望,即合乎理想的情況或結(jié)果。如:He ought to/should be here on timehe started early enough.他(應(yīng))該按時到這里他出發(fā)得夠早的了。We should arrive before dark.我們按說能在天黑前到達(dá)。The roads should be less crowded today.按說今天路上就不那么擁擠了。三、表示請求、允許、允諾1.當(dāng)對方是決策者時,你代表你(們)自己(I,we),或代表第三者(he,she,they)向?qū)Ψ?you)請示或提出建議時用:Shall/May(Might)/Can(Could)I/we.?Shall he/she/they.?Would/Will you.?如:Shall the driver wait outside?司機(jī)在外邊等著可以嗎?When shall my father be able to leave hospital?我父親什么時候可以出院?Would you do me a favor?請幫我一下,好嗎?2.could/might/would/should表委婉的語氣。如:Could/Might I use your bike tomorrow morning?Yes,you can/may.(否定:No,Im afraid not.)明天早晨我用一下你的自行車,行嗎?行,你用吧。(否定:不,恐怕不行。)不可以說:Yes,you could/might.回答允許時,用could/might表委婉是不恰當(dāng)?shù)摹?.shall與第二、三人稱連用,用于陳述句,表示說話者的命令、警告、威脅;當(dāng)宣布法律規(guī)定時,也用shall。You shall leave the room at once,and he also shall.(=I order you and him to leave the room at once.)你馬上離開這個房間,他也一樣。(說話者的命令)It has been announced that candidates shall remain in their seats until all the pa-pers have been collected.據(jù)宣布,在所有試卷收上來之前,應(yīng)試者必須待在自己的座位上。(規(guī)則或規(guī)定)四、表示必要性1.must 常用來表示必要性,意為“必須”,must do sth.(現(xiàn)在或?qū)?必須做某事。2.dont have to do sth./dont need to do sth./neednt do sth.(現(xiàn)在或?qū)?不必做某事。3.表示過去沒必要做某事時,分為以下情況:(1)neednt have done sth.本來不必做而做了某事(2)didnt have to do sth./didnt need to do sth./It was not necessary to do sth.(過去)不必做(不強(qiáng)調(diào)是否做了)某事You neednt have worked that late last night.It was harmful to your health.你昨晚本不必工作到那么晚。那對你的身體沒好處。Did you work very late last night?No,I didnt.I didnt need to work very late.你昨天晚上工作到很晚嗎?不是很晚。我沒必要工作到很晚。4.should也可以表示必要性,意為“(義務(wù)上)應(yīng)該”。should表示必要性時,在語氣上比must(必須)弱?！皊hould+動詞原形”表示現(xiàn)在或?qū)響?yīng)該做(的必要性);“should+have+過去分詞”表示過去本該做(的必要性)。如:I should go and visit him this afternoon,but I wonder if I will be free.今天下午我應(yīng)該去看望他,但我不知道我是否有空。(表示將來的必要性)You should have come to the conference yesterday.What was the reason for your absence?你昨天本應(yīng)該參加那個會議。你缺席的原因是什么?(表示過去的必要性)五、表示“寧愿做某事”時,可使用下面這些句式:would rather do sth.would rather do sth.than do sth.would do sth.ratherthan do sth.would rather sb.did sth.prefer to do sth.prefer to do sth.ratherthan do sth.prefer doing sth.to doing sth.高考中對這類用法的考查主要側(cè)重結(jié)構(gòu),因此要熟記其結(jié)構(gòu)。情態(tài)動詞+have done 用法例句must have done想必/準(zhǔn)是/一定做了否定式為:cant/couldnt+have doneIt must have rained last night,for the road is quite muddy.昨晚一定下雨了,因為路很泥濘。can/could have done1.本來能夠做2.過去可能會做Can he have gone to his aunts?他有可能去他姨媽家了嗎?cannot/could nothave done1.過去不可能2.過去沒能夠He cannot have forgotten it.他不可能忘了那件事。六、“情態(tài)動詞+have done”用法一覽表may/might have done也許/或許已經(jīng)做,一般只用于肯定句或否定句中(在否定句中表示“可能不”),不用于疑問句中。might則表示語氣更加不肯定。Its too late.I think he may have gone to bed.太晚了,我想他或許已經(jīng)睡了。He may not have finished thework.他也許還沒完成那項工。should/ought tohave done本該做而實際上未做You ought to have done this exercise more carefully.你本應(yīng)該更仔細(xì)地做這個練習(xí)。should not/ought notto have done本不該做而做了You shouldnt have told her the truth.你本不該告訴她真相。neednt have done本不必做而做了You neednt have taken a taxi here,for it was very near to my house.你本來不必打車來這里的,因為離我家很近。had better have done當(dāng)時最好做了(其否定式had better not have done表達(dá)相反的含義)You had better not have scold-ed her.要是那時你沒責(zé)罵她就好了。would rather have done寧愿當(dāng)時做了(其否定式would rather not have done表達(dá)相反含義,兩者都有“后悔”之意)I raised objections at the meet-ing,but now I would rather not have done that.我在會上提出了反對意見,但現(xiàn)在我寧愿沒那么做。would like/love tohave done sth.過去愿意做但未做成I would love to have gone to the party last night,but I had to work extra hours to finish a re-port.昨晚我本來很想去參加聚會的,但我得加班完成一個報告。七、情態(tài)動詞的其他用法要點:1.cannot but+do sth.表示“不得不,只好做某事”。如:I cannot but choose to go.我只好去。2.may well和may as well結(jié)構(gòu)。“may well+動詞原形”是一種常用結(jié)構(gòu),意為“完全能,很可能”,相當(dāng)于“be very likely to+動詞原形”。如:He may well be proud of his son.他大可為他的兒子感到自豪。Her appearance has changed so much that you may well not recognize her.她的模樣變化太大,你很可能認(rèn)不出她了?！癿ay as well+動詞原形”意為“最好,不妨,倒不如”。如:You may as well do it at once.你最好馬上就做這件事。We may as well stay where we are.我們留在現(xiàn)在的地方倒也不錯。3.cannot(或can never)與enough連用表示“再也不為過”。(具體用法見形容詞和副詞專題。)4.may可以用于祈使句,表示祝愿。如:May we never forget each other.愿我們彼此永不相忘。May you return in safety.愿你平安歸來。5.“Why/How+should”結(jié)構(gòu)表示說話人對某事不能理解,感到意外、驚訝等,意為“竟會”。如:Why should you be so late today?你今天怎么來得這么晚?How should I know?我怎么會知道?(意為:我不知道。)6.must表示“偏要,硬要”。如:Must you make so much noise?你非得弄出這么大聲響嗎?7.may作“可以”講時,其否定式常用“mustnt”表示“禁止”;must作“必須”講時,其否定式是“neednt”,表示“不必”。如:May I use your car?No,you mustnt.我能用用你的車嗎?不,一定不能。(委婉的拒絕可用:Sorry,but I am using it now.或Youd better not.等)Must I work out the problem tonight?No,you neednt.我今晚必須做出這道題嗎?不,不必。8.need和dare的用法need和dare兩者既可用作情態(tài)動詞也可用作實義動詞。作實義動詞時,有人稱和數(shù)的變化,可用于肯定句、否定句或疑問句中,構(gòu)成否定句或疑問句時要用助動詞do,does,did;作情態(tài)動詞時,沒有人稱和數(shù)的變化(dare的過去式為dared),直接接動詞原形,多用于否定句和疑問句中,構(gòu)成否定句和疑問句時不用助動詞。另外,dare作情態(tài)動詞時,還可用于條件狀語從句中,過去式為dared;作實義動詞時,dare用于疑問句或否定句,后面的to也可省略;I dare say是習(xí)慣說法,意為“我想,大概”。如:He neednt do it.(情態(tài)動詞)He doesnt need to do it.(實義動詞)他不必做這件事。I didnt know whether he dared say that to him.(情態(tài)動詞,有時態(tài)變化)我不知道他是否敢對他說那件事。He didnt dare(to)do it.(實義動詞)He dared not do it.(情態(tài)動詞)他不敢做這件事。注意:need作實義動詞時,還可表示“需要”,后接動名詞的主動形式表示被動含義(詳見非謂語動詞專題)。如:The floor needs sweeping.這地需要打掃了。知識清單二虛擬語氣一、虛擬語氣在非真實條件句中的運用 從句主句例句與現(xiàn)在事實相反的假設(shè)If+主語+動詞的過去式(be動詞用were)主語+should/would/could/might+動詞原形If I were you,I should seize the chance to go abroad.如果我是你,我就抓住這次出國的機(jī)會。與過去事實相反的假設(shè)If+主語+had+過去分詞主語+should/would/could/might+have+過去分詞If you had taken my advice,you would not have failed in the ex-ams.如果你早聽了我的建議,你考試就能通過了。與將來事實相反的假設(shè)1.If+主語+動詞的過去式2.If+主語+were to+動詞原形3.If+主語+should+動詞原形主語+should/would/could/might+動詞原形If he should not come tomorrow,we should put off the meeting till next Monday.如果明天他不來,我們就把會議推遲到下周一。使用虛擬條件句時要注意以下幾點:1.當(dāng)條件狀語從句表示的行為和主句表示的行為所發(fā)生的時間不一致時,被稱為“錯綜時間條件句”,動詞的形式要根據(jù)它所表示的時間作出相應(yīng)的調(diào)整。如:If you had followed my advice just now,you would be better now.如果你剛才聽了我的建議,你現(xiàn)在就好多了。If you had studied hard before,you would be a college student now.如果你以前努力學(xué)習(xí)的話,你現(xiàn)在早就是大學(xué)生了。2.if省略句在虛擬條件句中可省略if,把were,had,should提到句首,變?yōu)榈寡b句式。如:If I were at school again,I would study harder.Were I at school again,I would study harder.如果我還有上學(xué)的機(jī)會,我會更加努力地學(xué)習(xí)。If you had come earlier,you would have caught the bus.Had you come earlier,you would have caught the bus.如果你來得早些,你就能趕上公共汽車了。If it should rain tomorrow,we would not go climbing.Should it rain tomorrow,we would not go climbing.如果明天下雨的話,我們就不去登山了。注意:若省略的條件狀語從句中的謂語動詞是否定形式時,不能用動詞的縮略形式。如:我們可以說Were it not for the expense,I would go abroad now.但不能說Werent it for the expense,I would go abroad now.3.含蓄條件句有時為了表達(dá)的需要,在虛擬語氣中并不總是出現(xiàn)if引導(dǎo)的條件句,而是通過其他手段來代替條件句。如:What would you do with a million dollars(=if you had a million dollars)?如果你有100萬美元,你會做什么?Without your help,we couldnt have finished the work ahead of time.=But for your help,.=If it had not been for your help,.=Had it not been for your help,.沒有你的幫助,我們不可能提前完成這項工作。I was ill that day.Otherwise,I would have taken part in the sports meeting.(副詞)我那天病了。否則,我就參加運動會了。He telephoned to inform me of your birthday,or I would have known nothing about it.(連詞)他打電話通知了我你的生日,否則,我對此一點都不知道。I should have given you more help,but I was too busy.(連詞)我本應(yīng)該多幫幫你,但我(那時)太忙了。4.even if,even though 也可用于虛擬語氣,其形式與if從句在虛擬語氣中的形式相同。二、虛擬語氣在名詞性從句中的運用1.用于賓語從句中(1)wish后面的賓語從句一般用虛擬語氣,表示一種不可能實現(xiàn)的愿望。其謂語動詞構(gòu)成形式為:如:I wish(that)I were a bird and could fly freely in the sky.我希望我是一只小鳥,能在天空中自由飛翔。I wish(that)I had met that film star yesterday.我希望昨天見到那個影星了。How I wish it werent raining now!我多希望現(xiàn)在沒下雨啊!此外,If only+句子=How I wish+that從句。如:(wish)(wish)would(wish)一般過去時 賓語從句動作與同時過去完成時 賓語從句動作先于動詞原形 賓語從句動作后于If only I were a flying bird!=How I wish I were a flying bird!我要是一只飛鳥該多好啊!If only I had seen the film!=How I wish I had seen the film!我要是看了那部電影多好啊!(2)用于表示建議、愿望、命令等動詞后的賓語從句中,常見的動詞有:de-mand,order,require,insist,suggest,propose,advise等。賓語從句中的虛擬語氣結(jié)構(gòu)為“should+動詞原形”,should可以省略。如:He suggested that we(should)start off early the next day.他建議我們第二天早點出發(fā)。They insisted that the boy(should)go with them.他們堅決主張那個男孩子跟他們一起去。(3)在would rather后的賓語從句中,也用虛擬語氣,其構(gòu)成為would rather sb.+動詞過去式/had done(從句動作先發(fā)生)。如:I would rather they didnt hear of the news.我寧愿他們沒聽到那個消息。(4)當(dāng)suggest表示“暗示,表明”之意,insist表示“堅持說”之意時,suggest/in-sist后的賓語從句不使用虛擬語氣,應(yīng)使用陳述語氣。如:The smile on his face suggested that he was satisfied with our work.他臉上的微笑表明他對我們的工作很滿意。The man insisted that he had never stolen the money.那個人堅持說他沒有偷錢。在“It is desired/suggested/proposed/recommended/necessary/important/strange/natural/a pity/essential+that從句”結(jié)構(gòu)中,從句的謂語動詞用“should+動詞原形”,should可以省略。如:It is suggested that the meeting(should)be put off till next week.人們建議會議推遲到下周。It is strange that he (should)have acted toward his parents like that.(從句謂語動詞動作在主句謂語動詞動作之前發(fā)生時,從句謂語要用“should have+過去分詞”,should可以省略)真奇怪他竟然那樣對他的父母。注意:以上句式也可以用陳述語氣。如:Its a pity that you cant dance.2.用于主語從句中真遺憾你不會跳舞。3.用于表語從句和同位語從句中在suggestion,proposal,order,plan,idea,request,advice等名詞后的表語從句和同位語從句中要用虛擬語氣,其構(gòu)成是“should+動詞原形”,should可以省略。如:My idea is that we(should)think it over before accepting it.我的意見是在接受它之前我們要仔細(xì)考慮。We all agreed to his suggestion that we (should)go to Dalian for sightseeing.我們都同意他讓我們?nèi)ゴ筮B旅游的建議。如果as if/as though引導(dǎo)的從句謂語動詞與主句謂語動詞所表達(dá)的動作同時發(fā)生,從句用一般過去時;如果as if/as though引導(dǎo)的從句謂語動詞所表達(dá)的動作先于主句謂語動詞所表達(dá)的動作,從句用過去完成時;如果as if/as though引導(dǎo)的從句謂語動詞所表達(dá)的動作后于主句謂語動詞所表達(dá)的動作,從句謂語動詞用would+動詞原形。如:He looks as if he were an artist.(同時)他看起來像個藝術(shù)家。She speaks English so fluently as if she had studied English in America.(先于)她講英語如此流利,好像她在美國學(xué)過英語。He learns English so hard as if he would go to the U.S.A.(后于)他如此努力地學(xué)英語,好像他要去美國。易混點總結(jié)易混點總結(jié)一、as if/as though用在虛擬語氣中二、虛擬語氣用于定語從句中It is(high)time(that).句型中,定語從句的謂語動詞用過去式,或用“should+動詞原形”(其中should不能省略)。此句型意為“(現(xiàn)在)該”,用來表示提議。如:It is(high)time that you went to school.你該去上學(xué)了。It is(high)time that we should start out.我們該出發(fā)了。