2024屆高考英語一輪復習語法專練課件：9 情態動詞和虛擬語氣（牛津譯林版）
與過去事實相反的假 設 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 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.當條件狀語從句表示的行為和主句表示的行為所發生的時間不一致時,被稱 為“錯綜時間條件句”,動詞的形式要根據它所表示的時間作出相應的調 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 力學習的話,你現在早就是大學生了。 2.if省略句 在虛擬條件句中可省略if,把were,had,should提到句首,變為倒裝句式。如: If I were at school again,I would study harder. →Were I at school again,I would study harder. 如果我還有上學的機會,我會更加努力地學習。 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Weren't it for the expense,I would go abroad now. 3.含蓄條件句 有時為了表達的需要,在虛擬語氣中并不總是出現if引導的條件句,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 couldn't 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的愿望。其謂 語動詞構成形式為: ? 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 weren't raining now! 我多希望現在沒下雨啊! 此外,If only+句子=How I wish+that從句。如: 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 構為“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。 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,其構成為would rather sb.+動 詞過去式/had done(從句動作先發生)。如: I would rather they didn't hear of the news. 我寧愿他們沒聽到那個消息。 (4)當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”結構中,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: It's a pity that you can't 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 都同意他讓我們去大連旅游的建議。 如果as if/as though引導的從句謂語動詞與主句謂語動詞所表達的動作同時發 生,從句用一般過去時;如果as if/as though引導的從句謂語動詞所表達的動作 先于主句謂語動詞所表達的動作,從句用過去完成時;如果as if/as though引導 的從句謂語動詞所表達的動作后于主句謂語動詞所表達的動作,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) 他如此努力地學英語,好像他要去美國。 易混點總結 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“(現在)該……”,用來表示提 議。如: It is(high)time that you went to school. 你該去上學了。 It is(high)time that we should start out. 我們該出發了。 高頻考點一 情態動詞表能力
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1????(2024浙江,4)It was so noisy that we ????hear ourselves speak. ?答案 couldn't ?解析 句意:這里如此嘈雜以至于我們無法聽到自己說話。根據語境可知此 處表達過去的能力故用couldn't。 考點清單 ? 高頻考點二 情態動詞表推測 情態動詞表推測分為:對現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。對現在情況的肯定推測就用must,否定推測 就用can't,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can't 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,還要判斷出是對現在還是對過 去情況的推測。 典例2????(2024重慶,12)You ????be Carol.You haven't 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。根據語境可 知此處表示對現在情況的肯定推測,所以要用must(一定)。 ? 高頻考點三 情態動詞表請求、許諾、允許 1.向對方提出或征求意見時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 示按照規章制度、法律、條例規定應該怎么做也要用shall。這是高考對shall 的考查熱點。 典例3????(2024北京,27)????I have a word with you?It won't 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。本題考查情態動詞的 基本用法。can/may可以,表請求允許。 ? 高頻考點四 情態動詞表必要性 must語氣最強烈,表示說話者堅決認為必須做某事;need語氣要比must弱,表示 說話者認為有必要做某事;should在表示該含義時,表示在義務上應該做某 事。should還表示“竟然會,(將來)萬一”。 典例4????(2024北京,29)—Can't you stay a little longer? —It's 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。我現在 確實得走了。我的女兒獨自一人在家。根據對話內容可知空格處表示“必要 性”,故用must。 ? 情態動詞+have done 意義 must have done 想必/準是/一定做了 否定式為can't/couldn't have done could have done 本來能夠做 can/could have done 過去可能會做 cannot/could not have done 1.過去不可能做 2.過去沒能夠做 may/might have done 也許/或許已經做了……,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 情態動詞+have done should/ought to have done 本該做而實際上未做 shouldn't/ought not to have done 本不該做而做了 needn't have done 本來不必做而做了 had better have done 要是當時做了就好了,用于事后的遺憾,含輕微的責備,其否定式had better not have done表達相反的含義 would rather have done 寧愿當時做了,其否定式would rather not have done表達相反的含義,兩者都表示“后悔”之意 would like/love to have done 過去愿意做但未做成 典例5????(2024天津,7)I ????have worried before I came to the new school,for my classmates here are very friendly to me. ?答案 needn't ?解析 句意:在進入這所新學校之前我本沒必要擔心,因為這里的同學對我 很友好。根據語境可知此處表達“過去對某事擔心過,但現在看來這種擔心 沒有必要”,應該用needn't have done。 ? 高頻考點六 虛擬語氣
虛擬語氣是用來表示與現在或過去的實際情況相反的假設,近年來主要是考 查上述兩點,而對將來可能情況的假設已很少涉及。注意下列幾種情況: 1.表示與現在實際情況相反的假設:條件從句謂語動詞應該用一般過去時(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:條件從句謂語動詞應該用過去完成時,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,常常考查把 should去掉的情況。與這些特殊動詞相關的名詞形式后的that引導的同位語 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構:wish句式,as if/though句式,would rather...,It's high time...等。 典例6????(2024北京,34)If I ????(see)it with my own eyes,I wouldn't have be- lieved it. ?答案 hadn't 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“wouldn't
have believed”可知此處為與過去事實相反的假設,故if從句謂語動詞應為 hadn't seen。 ? 知識清單一 情態動詞的用法要點 一、表能力 ? 如: I am starving to death.I can eat two bowls of rice now.(現在的能力) 我快餓死了,現在我能吃兩碗米飯。 If you have a good sleep,you will be able to work out this problem.(將來的能力) 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生,此種用法常常可以說明人 或事物的特征。情態動詞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生的可能性: (1)表示具體事情實際發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 按說應該 應該不會 / ought to 按說應該 應該不會 / 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 can't/couldn't 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 didn't 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 Jeff's party? —I'm 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,而表示可能性弱于它們相應的現 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 果。如: He ought to/should be here on time—he started early enough. 他(應)該按時到這里——他出發得夠早的了。 We should arrive before dark. 我們按說能在天黑前到達。 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)向對 方(you)請示或提出建議時用:①Shall/May(Might)/Can(Could)I/we...?②Shall he /she/they...?③Would/Will you...?如: Shall the driver wait outside? 司機在外邊等著可以嗎? 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,I'm 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表委婉是不恰當的。 3.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 宣布法律規定時,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. 據宣布,在所有試卷收上來之前,應試者必須待在自己的座位上。(規則或規 定) 四、表示必要性 1.must 常用來表示必要性,意為“必須”,must do sth.(現在或將來)必須做某 事。 2.don't have to do sth./don't need to do sth./needn't do sth.(現在或將來)不必做 某事。 3.表示過去沒必要做某事時,分為以下情況: (1)needn't have done sth.本來不必做而做了某事 (2)didn't have to do sth./didn't need to do sth./It was not necessary to do sth.(過 去)不必做(不強調是否做了)某事 You needn't 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 didn't.I didn't 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“(義務上)應該”。should表示必要性時,在 語氣上比must(必須)弱。“should+動詞原形”表示現在或將來應該做(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: ? ? 高考中對這類用法的考查主要側重結構,因此要熟記其結構。 情態動詞+have done 用法 例句 must have done 想必/準是/一定做了否定式為:can't/couldn't+have done It 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 done 1.本來能夠做 2.過去可能會做 Can he have gone to his aunt's? 他有可能去他姨媽家了嗎? cannot/could not have done 1.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、“情態動詞+have done”用法一覽表 may/might have done 也許/或許已經做……,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。 It's too late.I think he may have gone to bed.太晚了,我想他或許已經睡了。 He may not have finished the work.他也許還沒完成那項工。 should/ought to have done 本該做而實際上未做 You ought to have done this exercise more carefully.你本應該更仔細地做這個練習。 should not/ought not to have done 本不該做而做了 You shouldn't have told her the truth. 你本不該告訴她真相。 needn't have done 本不必做而做了 You needn't 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 當時最好做了(其否定式had better not have done表達相反 的含義) You had better not have scold- ed her. 要是那時你沒責罵她就好 了。 would rather have done 寧愿當時做了(其否定式 would rather not have done表 達相反含義,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 現在我寧愿沒那么做。 would like/love to have 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結構。 “may well+動詞原形”是一種常用結構,意為“完全能,很可能”,相當于“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,你很可能認不出她了。 “may 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”結構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“mustn't”表示“禁止”;must作“必 須”講時,其否定式是“needn't”,表示“不必”。如: —May I use your car? —No,you mustn't. ——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You'd better not.等) —Must I work out the problem tonight? —No,you needn't. ——我今晚必須做出這道題嗎? ——不,不必。 8.need和dare的用法 need和dare兩者既可用作情態動詞也可用作實義動詞。作實義動詞時,有人稱 和數的變化,可用于肯定句、否定句或疑問句中,構成否定句或疑問句時要用 助動詞do,does,did;作情態動詞時,沒有人稱和數的變化(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,構成否定句和疑問句時不用助動 詞。 另外,dare作情態動詞時,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是習慣說法,意為 “我想,大概”。如: He needn't do it.(情態動詞) He doesn't need to do it.(實義動詞) 他不必做這件事。 I didn't know whether he dared say that to him.(情態動詞,有時態變化) 我不知道他是否敢對他說那件事。 He didn't dare(to)do it.(實義動詞) He dared not do it.(情態動詞) 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 與現在事實相反的假 設 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 這次出國的機會。
與過去事實相反的假 設 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 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.當條件狀語從句表示的行為和主句表示的行為所發生的時間不一致時,被稱 為“錯綜時間條件句”,動詞的形式要根據它所表示的時間作出相應的調 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 力學習的話,你現在早就是大學生了。 2.if省略句 在虛擬條件句中可省略if,把were,had,should提到句首,變為倒裝句式。如: If I were at school again,I would study harder. →Were I at school again,I would study harder. 如果我還有上學的機會,我會更加努力地學習。 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Weren't it for the expense,I would go abroad now. 3.含蓄條件句 有時為了表達的需要,在虛擬語氣中并不總是出現if引導的條件句,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 couldn't 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的愿望。其謂 語動詞構成形式為: ? 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 weren't raining now! 我多希望現在沒下雨啊! 此外,If only+句子=How I wish+that從句。如: 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 構為“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。 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,其構成為would rather sb.+動 詞過去式/had done(從句動作先發生)。如: I would rather they didn't hear of the news. 我寧愿他們沒聽到那個消息。 (4)當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”結構中,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: It's a pity that you can't 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 都同意他讓我們去大連旅游的建議。 如果as if/as though引導的從句謂語動詞與主句謂語動詞所表達的動作同時發 生,從句用一般過去時;如果as if/as though引導的從句謂語動詞所表達的動作 先于主句謂語動詞所表達的動作,從句用過去完成時;如果as if/as though引導 的從句謂語動詞所表達的動作后于主句謂語動詞所表達的動作,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) 他如此努力地學英語,好像他要去美國。 易混點總結 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“(現在)該……”,用來表示提 議。如: It is(high)time that you went to school. 你該去上學了。 It is(high)time that we should start out. 我們該出發了。 高頻考點一 情態動詞表能力
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1????(2024浙江,4)It was so noisy that we ????hear ourselves speak. ?答案 couldn't ?解析 句意:這里如此嘈雜以至于我們無法聽到自己說話。根據語境可知此 處表達過去的能力故用couldn't。 考點清單 ? 高頻考點二 情態動詞表推測 情態動詞表推測分為:對現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。對現在情況的肯定推測就用must,否定推測 就用can't,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can't 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,還要判斷出是對現在還是對過 去情況的推測。 典例2????(2024重慶,12)You ????be Carol.You haven't 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。根據語境可 知此處表示對現在情況的肯定推測,所以要用must(一定)。 ? 高頻考點三 情態動詞表請求、許諾、允許 1.向對方提出或征求意見時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 示按照規章制度、法律、條例規定應該怎么做也要用shall。這是高考對shall 的考查熱點。 典例3????(2024北京,27)????I have a word with you?It won't 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。本題考查情態動詞的 基本用法。can/may可以,表請求允許。 ? 高頻考點四 情態動詞表必要性 must語氣最強烈,表示說話者堅決認為必須做某事;need語氣要比must弱,表示 說話者認為有必要做某事;should在表示該含義時,表示在義務上應該做某 事。should還表示“竟然會,(將來)萬一”。 典例4????(2024北京,29)—Can't you stay a little longer? —It's 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。我現在 確實得走了。我的女兒獨自一人在家。根據對話內容可知空格處表示“必要 性”,故用must。 ? 情態動詞+have done 意義 must have done 想必/準是/一定做了 否定式為can't/couldn't have done could have done 本來能夠做 can/could have done 過去可能會做 cannot/could not have done 1.過去不可能做 2.過去沒能夠做 may/might have done 也許/或許已經做了……,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 情態動詞+have done should/ought to have done 本該做而實際上未做 shouldn't/ought not to have done 本不該做而做了 needn't have done 本來不必做而做了 had better have done 要是當時做了就好了,用于事后的遺憾,含輕微的責備,其否定式had better not have done表達相反的含義 would rather have done 寧愿當時做了,其否定式would rather not have done表達相反的含義,兩者都表示“后悔”之意 would like/love to have done 過去愿意做但未做成 典例5????(2024天津,7)I ????have worried before I came to the new school,for my classmates here are very friendly to me. ?答案 needn't ?解析 句意:在進入這所新學校之前我本沒必要擔心,因為這里的同學對我 很友好。根據語境可知此處表達“過去對某事擔心過,但現在看來這種擔心 沒有必要”,應該用needn't have done。 ? 高頻考點六 虛擬語氣
虛擬語氣是用來表示與現在或過去的實際情況相反的假設,近年來主要是考 查上述兩點,而對將來可能情況的假設已很少涉及。注意下列幾種情況: 1.表示與現在實際情況相反的假設:條件從句謂語動詞應該用一般過去時(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:條件從句謂語動詞應該用過去完成時,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,常常考查把 should去掉的情況。與這些特殊動詞相關的名詞形式后的that引導的同位語 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構:wish句式,as if/though句式,would rather...,It's high time...等。 典例6????(2024北京,34)If I ????(see)it with my own eyes,I wouldn't have be- lieved it. ?答案 hadn't 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“wouldn't
have believed”可知此處為與過去事實相反的假設,故if從句謂語動詞應為 hadn't seen。 ? 知識清單一 情態動詞的用法要點 一、表能力 ? 如: I am starving to death.I can eat two bowls of rice now.(現在的能力) 我快餓死了,現在我能吃兩碗米飯。 If you have a good sleep,you will be able to work out this problem.(將來的能力) 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生,此種用法常常可以說明人 或事物的特征。情態動詞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生的可能性: (1)表示具體事情實際發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 按說應該 應該不會 / ought to 按說應該 應該不會 / 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 can't/couldn't 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 didn't 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 Jeff's party? —I'm 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,而表示可能性弱于它們相應的現 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 果。如: He ought to/should be here on time—he started early enough. 他(應)該按時到這里——他出發得夠早的了。 We should arrive before dark. 我們按說能在天黑前到達。 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)向對 方(you)請示或提出建議時用:①Shall/May(Might)/Can(Could)I/we...?②Shall he /she/they...?③Would/Will you...?如: Shall the driver wait outside? 司機在外邊等著可以嗎? 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,I'm 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表委婉是不恰當的。 3.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 宣布法律規定時,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. 據宣布,在所有試卷收上來之前,應試者必須待在自己的座位上。(規則或規 定) 四、表示必要性 1.must 常用來表示必要性,意為“必須”,must do sth.(現在或將來)必須做某 事。 2.don't have to do sth./don't need to do sth./needn't do sth.(現在或將來)不必做 某事。 3.表示過去沒必要做某事時,分為以下情況: (1)needn't have done sth.本來不必做而做了某事 (2)didn't have to do sth./didn't need to do sth./It was not necessary to do sth.(過 去)不必做(不強調是否做了)某事 You needn't 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 didn't.I didn't 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“(義務上)應該”。should表示必要性時,在 語氣上比must(必須)弱。“should+動詞原形”表示現在或將來應該做(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: ? ? 高考中對這類用法的考查主要側重結構,因此要熟記其結構。 情態動詞+have done 用法 例句 must have done 想必/準是/一定做了否定式為:can't/couldn't+have done It 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 done 1.本來能夠做 2.過去可能會做 Can he have gone to his aunt's? 他有可能去他姨媽家了嗎? cannot/could not have done 1.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、“情態動詞+have done”用法一覽表 may/might have done 也許/或許已經做……,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。 It's too late.I think he may have gone to bed.太晚了,我想他或許已經睡了。 He may not have finished the work.他也許還沒完成那項工。 should/ought to have done 本該做而實際上未做 You ought to have done this exercise more carefully.你本應該更仔細地做這個練習。 should not/ought not to have done 本不該做而做了 You shouldn't have told her the truth. 你本不該告訴她真相。 needn't have done 本不必做而做了 You needn't 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 當時最好做了(其否定式had better not have done表達相反 的含義) You had better not have scold- ed her. 要是那時你沒責罵她就好 了。 would rather have done 寧愿當時做了(其否定式 would rather not have done表 達相反含義,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 現在我寧愿沒那么做。 would like/love to have 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結構。 “may well+動詞原形”是一種常用結構,意為“完全能,很可能”,相當于“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,你很可能認不出她了。 “may 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”結構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“mustn't”表示“禁止”;must作“必 須”講時,其否定式是“needn't”,表示“不必”。如: —May I use your car? —No,you mustn't. ——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You'd better not.等) —Must I work out the problem tonight? —No,you needn't. ——我今晚必須做出這道題嗎? ——不,不必。 8.need和dare的用法 need和dare兩者既可用作情態動詞也可用作實義動詞。作實義動詞時,有人稱 和數的變化,可用于肯定句、否定句或疑問句中,構成否定句或疑問句時要用 助動詞do,does,did;作情態動詞時,沒有人稱和數的變化(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,構成否定句和疑問句時不用助動 詞。 另外,dare作情態動詞時,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是習慣說法,意為 “我想,大概”。如: He needn't do it.(情態動詞) He doesn't need to do it.(實義動詞) 他不必做這件事。 I didn't know whether he dared say that to him.(情態動詞,有時態變化) 我不知道他是否敢對他說那件事。 He didn't dare(to)do it.(實義動詞) He dared not do it.(情態動詞) 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 與現在事實相反的假 設 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 這次出國的機會。
