第三講情態(tài)動詞和虛擬語氣情態(tài)動詞的基本用法全析考法 單句語法填空/單句改錯1(2018北京高考)In todays information age, the loss of data _ cause serious problems for a pany. 解析：can句意：在如今的信息化時代，丟失數(shù)據(jù)可能會給一個公司造成嚴重的問題。can在此表示客觀可能性，意為“可能會，有時候會”。2(2016全國卷)Truly elegant chopsticks might _ (make) of gold and silver with Chinese characters.解析： be made根據(jù)語境可知，筷子是被制造的。此處為含有情態(tài)動詞的被動語態(tài)might be done。3(2015四川高考改編)You _ be careful with the camera.It costs!解析：must句意：你必須要小心使用這個相機。它很貴重！ 根據(jù)后面的“It costs！”可知，此處是說話人對使用相機的人提出的要求，must意為“必須”，表示說話人主觀上的要求，語氣強烈。4(2018全國卷)As a kid, I loved to watch cartoons, but no matter how many times I asked to watch them, my parents would not to let me._解析：去掉let前的to情態(tài)動詞would表示“意愿”時后面直接接動詞原形。5(2016全國卷)We can chose between staying at home and taking a trip._解析：chosechoose情態(tài)動詞can后面接動詞原形。chose是choose的過去式形式。謹記規(guī)則(一)can, could用法例句表示能力，意為“能，會”；could表示過去的能力。She can speak French fluently. 她能講一口流利的法語。can可用于肯定句中，表示客觀或理論上的可能性。An experienced teacher can make mistakes. 一位有經(jīng)驗的老師也會犯錯。表示請求或允許。在疑問句中，could可以代替can，語氣更委婉，肯定回答時要用can，不用could。Can/Could I use your bike tomorrow morning？Yes, you can. 明天上午我可以用你的自行車嗎？是的，可以。表示說話者的主觀推測，意為“可能”，用于否定句和疑問句中。can比could語氣強。He cant be our manager. He has gone to Beijing. 他不可能是我們經(jīng)理。他已經(jīng)去北京了。表示驚異、懷疑、迷惑等態(tài)度，常用于否定句和疑問句中。How can you treat me like that？你怎么能那樣對我？用于固定習語中：cant . too/enough (無論也不過分；越越好)；cant but do sth. (不得不，只好)；cant help doing sth. (禁不住做某事)。I cant thank you too much for all your help to my son while we were away from home.我非常感謝你，在我們不在家時幫助我的兒子。One cannot but admire her determination.人們不得不佩服她的決心。(二)may, might用法例句表示請求或許可。在疑問句中，might可以代替may，語氣更加委婉。給予許可時用may，不用might。Might I ask for a picture of your little daughter？Yes, you may我可以要一張你小女兒的照片嗎？是的，可以。表示推測，意為“或許，可能”，通常用于肯定句和否定句中。might比may語氣弱。I really dont like James. Why did you invite him？Dont worry. He might not e. 我真的不喜歡詹姆斯。你為什么邀請他？別擔心。他或許不會來。表示祝愿，常用結(jié)構(gòu)為：May主語動詞原形！May you be happy every day！愿你快樂每一天！用于固定短語中：may/might as well動詞原形(不妨，還是為好)；may/might well動詞原形(很可能)。You may/might as well tell him the truth.你不妨告訴他事實吧。He may/might well stay in Beijing now.他現(xiàn)在很可能待在北京。(三)must, have to用法例句表示義務(wù)，意為“必須”。must強調(diào)說話人的主觀看法，have to則強調(diào)客觀需要；在回答帶有must的問句時，否定式常用need not (neednt)或dont have to，而不是用must not。We must act as quickly as possible now. Just tell us whether you can undertake the task or not.現(xiàn)在我們必須盡快采取行動。你僅僅告訴我們你能否承擔這項任務(wù)就行。I have to go now, because my mother is in hospital.我現(xiàn)在不得不走了，因為我母親在住院。must用來表示推測，意為“一定”，只能用在肯定句中。must的肯定程度比can強。You must be hungry after a long walk. 長途跋涉之后，你一定餓了。must表示“偏要，非要不可”。常用于疑問句和條件句中，偶爾也用于陳述句中。If you must go, at least wait until the storm is over. 如果你非要走，至少要等到暴風雨停了。mustnt表示禁止，意為“不得，不允許；一定不要”。You mustnt play with the knife, or you may hurt yourself.你千萬不要玩刀，否則會傷到自己的。(四)shall用法例句用于第一、三人稱的疑問句中，表示說話者征求對方的意見。Shall he e in now？要不要讓他現(xiàn)在進來？用于第二、三人稱的陳述句中，表示說話者的命令、警告、威脅、允諾、決心等。You shall be punished for what you have done.你必須為你的所作所為受到懲罰。用于條約、規(guī)定、法令、法律等文件中表示義務(wù)規(guī)定，意為“必須”。One of our rules is that every student shall wear school uniform while at school. 我們有一條規(guī)定，那就是每名學生在校期間都必須穿校服。(五)should, ought to用法例句should表示責任、義務(wù)、勸告、建議等，意為“應(yīng)該”。We should be strict with ourselves.我們應(yīng)該嚴格要求自己。should表示出乎意料、驚訝的口氣，意為“竟然，居然”。Such a gentleman should do that.這樣一位紳士竟然會做那種事。ought to表示義務(wù)、責任、勸告等，意為“應(yīng)該”，語氣比should略重。You ought not to be so selfish. 你不應(yīng)該這么自私。should和ought to表示推測，指合乎理想的情況或結(jié)果，意為“按說應(yīng)該”。Try phoning Robert he should be home by now. 給羅伯特打個電話試試，他現(xiàn)在應(yīng)該到家了。(六)will, would用法例句與各種人稱連用，用于陳述句中，表示主語的意志、意愿或決心。will指現(xiàn)在，would指過去。I will never talk to him again. 我再也不會和他說話了。表示征求意見或提出請求，多用于第二人稱疑問句中。would比will語氣委婉。Will/Would you please close the window？請把窗戶關(guān)上好嗎？表示習慣性動作、固有屬性或必然趨勢，意為“總是；習慣于”。will指現(xiàn)在，would指過去。Fish will die without water.沒有水，魚會死的。(七)need, dare用法例句need既可作情態(tài)動詞，也可作實義動詞；作情態(tài)動詞時，表示“需要”，常用于否定句、疑問句和條件句中。neednt表示“不必”；對need引出的一般疑問句作肯定回答時用must而不用need，作否定回答時用neednt。I neednt use a clock to wake me up, because at six oclock each morning the train es by my house. 我不必用鬧鐘來叫醒自己，因為每天早上六點都有火車從我家旁邊經(jīng)過。dare既可作情態(tài)動詞，也可作實義動詞；作情態(tài)動詞時，表示“敢，敢于”，后跟動詞原形，常用于疑問句、否定句和條件句中。I am so afraid that I dare not move. 我嚇得一動也不敢動。情態(tài)動詞have done全析考法單句語法填空/單句改錯1(2018天津高考改編)I cant find my purse. I could _ (leave) it in the supermarket yesterday, but Im not sure.解析：have left句意：我找不到我的錢包了。我昨天可能把它落在超市里了，但我不確定。根據(jù)句中的時間狀語yesterday可知空格處是對過去發(fā)生事情的推測，需用“情態(tài)動詞have done”。2(2013全國卷改編)Since nobody gave him any help, he _ have done the research on his own.解析：must句意：既然沒有人幫助他，他一定是獨自完成了這項研究。根據(jù)題干中“Since nobody gave him any help”可判斷設(shè)空處表示肯定的推測。3(2013浙江高考改編)I _ (enjoy) myself more it was a perfect day.解析：couldnt/cant have enjoyed句意：我玩得再開心不過了這是完美的一天?！癱ant/couldnt . more”表示最高級的意思；根據(jù)題干中的was可知設(shè)空處表示“對過去發(fā)生的事情的態(tài)度”，故答案為couldnt/cant have enjoyed。4(2015天津高考改編)I neednt worried before I came to the new school, for my classmates here are very friendly to me._解析：worried前加haveneednt have done表示“本沒有必要做”。謹記規(guī)則1對過去發(fā)生的事情或狀態(tài)進行推測must have done sth.“(過去)一定做了某事”；語氣比較肯定；用于肯定句may (might) have done sth.“(過去)可能/也許做了某事”；語氣不確定；用于肯定句和否定句can (could) have done sth.“本來能夠/可以做某事”；用于否定句和疑問句，表示對過去發(fā)生的行為的懷疑或不確定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。The boy might have known the truth, but I am not quite sure.那個男孩也許知道了真相，但我不是很確定。I didnt see her in the meeting room this morning. She couldnt have spoken at the meeting.我今天上午沒在會議室看見她，她不可能在會議上講話。2表示“與過去事實相反”could have done sth.過去本可以做某事但實際上沒做neednt have done sth.過去本不必做某事但實際上做了ought to/should have done sth.過去本應(yīng)該做某事但實際上沒做oughtnt to/shouldnt have done sth.過去本不應(yīng)該做某事但實際上做了might have done sth.過去可能做某事但實際上沒做You could have done better, but you didnt try your best.你本可以做得更好，但是你沒有盡力而為。I neednt have taken the umbrella, for the weather is fine.天氣這么好，我本沒必要帶雨傘的。You ought to have done this exercise more carefully.你本應(yīng)該更仔細地做這個練習。You might have given him more help, though you were busy.你本可以給他更多幫助，雖然你當時很忙。虛擬語氣全析考法單句語法填空/單句改錯1(2018北京高考改編)They might have found a better hotel if they _ (drive) a few more kilometers. 解析：had driven句意：如果他們開車再多走幾千米的話，他們或許就會找到一家更好的旅館。主從句皆為對過去的虛擬，從句中應(yīng)使用過去完成時表示對過去的虛擬。2(2018天津高考改編)If we _ (catch) the flight yesterday, we would be enjoying our holiday on the beach now. 解析：had caught句意：如果昨天我們趕上了航班的話，我們現(xiàn)在正在海灘上享受我們的假期了。此句是錯綜時間虛擬語氣，由yesterday可知從句是對過去的虛擬(用過去完成時)，主句是對現(xiàn)在的虛擬。3(2018江蘇高考改編)Its strange that he _have taken the books without the owners permission. 解析：should句意：真奇怪，他居然沒有得到主人的允許就把那些書拿走了。在it is strange that .; it is important that .; it is necessary that .等句式中，that 引導(dǎo)的從句要用“should動詞原形”作謂語。4(2018江蘇高考改編)There is a good social life in the village, and I wish I _ (have) a second chance to bee more involved. 解析：had句意：在這個村子里有很好的社交生活，并且我希望我能再有一次機會更多地參與其中。動詞wish后面的賓語從句要用虛擬語氣。若表示與現(xiàn)在相反的虛擬，從句用一般過去時； 若表示與過去相反的虛擬，從句用過去完成時或would/could have done。根據(jù)句意可知，此處表示與現(xiàn)在的情況相反，故用動詞的過去式。5(2016全國卷)Some classmates suggest we can go to places of interest nearby._解析：canshould或去掉cansuggest在此處表示“建議”，后面接賓語從句時，從句中謂語用“should動詞原形”，should可以省略。6(2015四川高考)If you are me, would you talk to them？_解析：arewere根據(jù)語境可知，此處是虛擬語氣，表示對現(xiàn)在的虛擬，動詞用過去式，所以要把are改為were。謹記規(guī)則(一)虛擬條件句的基本用法1if虛擬條件句(1)基本構(gòu)成時間if從句謂語動詞形式主句謂語動詞形式對現(xiàn)在的虛擬過去式(be的過去式用were)should/would/could/might動詞原形對過去的虛擬had過去分詞should/would/could/mighthave過去分詞對將來的虛擬should動詞原形should/would/could/might動詞原形過去式(be的過去式用were)were to動詞原形(2)錯綜時間虛擬條件句當從句、主句所表示的行為發(fā)生的時間不一致時，動詞的形式要根據(jù)它所在的時間作出相應(yīng)的調(diào)整。If you hadnt left home without a word, your parents wouldnt be so worried now.要不是你一言不語地離開家，你父母現(xiàn)在就不會那么擔心了。(從句與過去事實相反，主句與現(xiàn)在事實相反)(3)省略if的倒裝句if虛擬條件狀語從句中出現(xiàn)were, had, should時，可省略if，把were, had, should提到句首，變?yōu)榈寡b句式。Had he caught the morning train, he would not have been late for the meeting.要是他趕上了早晨的火車，那他就不會開會遲到了。2含蓄條件句(1)有時假設(shè)的情況不用條件句表達，而是用but for, without等介詞(短語)或上下文來表示。We wouldnt have finished the project on time without your timely help.如果沒有你的及時幫助，我們就不能按時完成那項工程了。(2)用連詞otherwise, or等暗示后文與前面的情況相反，從而引出后文的虛擬語氣。I was ill that day. Otherwise, I would have taken part in the sports meeting.我那天病了，否則，我就參加運動會了。(3)虛擬條件通過but暗示出來，模式為“虛擬情況but真實情況”。I would have delivered a speech, but I had a cold that day.我本來可以演講的，但是那天我感冒了。(二)虛擬語氣在名詞性從句中的用法1主語從句中的虛擬語氣(1)某些It is/was形容詞/過去分詞/名詞that引導(dǎo)的主語從句中，主語從句要用虛擬語氣，即“should動詞原形”，should可省略。Its vital that we (should) take our safety driving along the road seriously.重要的是我們應(yīng)該認真對待我們的安全駕駛。(2)用于本句型常見的形容詞、過去分詞、名詞形容詞necessary, important, best, right, impossible, preferable, desirable, advisable, essential, urgent, strange等。過去分詞通常表示提議、要求、命令等，如suggested, required, requested, demanded, urged, decided, proposed, ordered, desired, advised等。名詞pity, regret, desire, rule, shame, honour, surprise等。2賓語從句中的虛擬語氣(1)賓語從句在表示“提議”“要求”“命令”“意志”等動詞后，其謂語動詞用“(should)動詞原形”表示虛擬。常見的此類動詞有insist (堅持要求，堅決主張), order, mand, advice, suggest (建議), propose, remend, ask, demand, require, request, urge, arrange, desire, intend, direct等。He suggested that we (should) start off early the next day.他建議我們第二天早點出發(fā)。易錯提醒當suggest表示“暗示，表明”之意，insist表示“堅持說，堅持認為”之意時，suggest/insist后的賓語從句不使用虛擬語氣，而使用陳述語氣。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.那個人堅持說他從沒有偷過那筆錢。(2)wish后接that引導(dǎo)的賓語從句用虛擬語氣，其謂語動詞的形式為：時間從句謂語動詞形式對現(xiàn)在的虛擬過去式(be的過去式用were)對過去的虛擬had過去分詞對將來的虛擬would/could/might動詞原形I wish (that) I were ten years younger.但愿我能年輕十歲。I wish (that) I had met that film star yesterday.我多希望昨天見到了那個電影明星。(3)would rather后接賓語從句用虛擬語氣，其謂語動詞的形式為：時間從句謂語動詞形式對現(xiàn)在的虛擬過去式(be的過去式用were)對將來的虛擬對過去的虛擬had過去分詞,Id rather he had gone to the seaside with me the day before yesterday.要是他前天和我去海邊就好了。3表語從句中的虛擬語氣(1)句子主語是表示“愿望”“勸告”“建議”“主張”“命令”“決定”等行為動詞派生出來的同根名詞時，其表語從句常用虛擬語氣“(should)動詞原形”結(jié)構(gòu)。這類名詞有suggestion, proposal, request, advice, decision, requirement等。Our only request is that this (should) be settled as soon as possible.我們唯一的要求是這事應(yīng)該盡可能快地解決。(2)虛擬語氣可用于as if, as though引導(dǎo)的表語從句和方式狀語從句：時間從句謂語動詞形式對現(xiàn)在的虛擬過去式(be的過去式用were)對過去的虛擬had過去分詞對將來的虛擬would/could/might動詞原形She looks as if nothing had happened to her.她看起來好像什么事都沒有發(fā)生似的。He opened his mouth as if he would say something.他張開嘴好像要說什么。特別注意如果從句中描述的事情可能會發(fā)生，那么從句中的謂語動詞可用陳述語氣。It sounds as if it is raining.聽起來像是在下雨。4同位語從句中的虛擬語氣當表示建議、提議、命令、要求等的名詞作主語或賓語時，其同位語從句中的謂語動詞用“should動詞原形”，should可以省略。常見的這類名詞有：advice建議decision決定demand要求desire渴望 idea想法 motion提議order命令 plan計劃 proposal提議request要求 suggestion建議We agreed to the order that the task (should) be pleted at 5 oclock.我們都同意這個命令：五點完成這項任務(wù)。52個特定句式中的虛擬語氣(1)if only引導(dǎo)的條件句及感嘆句對過去的虛擬對現(xiàn)在的虛擬對將來的虛擬had過去分詞過去式(be的過去式用were)would/could/should/might動詞原形(2)It is (high/about/(very) time (that).從句中謂語動詞用過去式或“should動詞原形”。If only I had seen the film.要是我看過那部電影就好了。It is high time that we should start/started out.我們該出發(fā)了。語法填空解題“2注意”1若句中謂語動詞為原形，在其前設(shè)純空格題時，注意考慮情態(tài)動詞。然后根據(jù)句意或句式結(jié)構(gòu)填入恰當?shù)那閼B(tài)動詞。2一旦判斷所給動詞在句中作謂語，就要考慮其時態(tài)、語態(tài)、語氣、主謂一致等，特別是注意虛擬語氣中的時態(tài)。判斷虛擬語氣，除了常見的if虛擬條件句，還應(yīng)注意其他常搭配虛擬語氣的標志詞， 如suggest, would rather, as if, wish, otherwise, or, but for等。據(jù)第1條解題1You can never be too careful while driving. You know, many traffic accidents result from carelessness.2Youve made lots of mistakes in the exam, many of which could have been avoided had you been more careful.3As the new manager is kind and patient, there should be no trouble in his getting on well with the workers.4Smoking is not allowed here, sir. Go to the smoking room over there, if you must.5Who is playing the piano?It must be Kate. No one else in our school can play it so beautifully.據(jù)第2條解題6It is required by law that a driving test (should)be_taken (take) before a man gets a license.7He telephoned to inform me of your birthday, or I would_have_known (know) nothing about it.8The national smog serves as a constant reminder, indicating that its high time we reflected (reflect) on ourselves.9It would_be (be) cool if I won this contest. I dont think Im good enough, though.Give it a shot. You never know.10The Antarctica is so mystically described by some people. If only I had_been (be) there before.短文改錯解題“2視角”1看句中情態(tài)動詞是否運用正確；2看是否考查虛擬語氣。若是考查虛擬語氣，注意分清主句與從句中的時態(tài)關(guān)系以及不同句式中的虛擬語氣構(gòu)成形式。據(jù)第1條解題1Life is unpredictable; even the poorest may to bee the richest.去掉to2I love the weekend, because I neednt to get up early on Saturdays and Sundays.去掉to3We neednt bought so much food now that Suzie wont be with us for dinner.bought前加have據(jù)第2條解題4One day, a friend of mine, Tom, contacted me and suggested that we started to swim.startedstart5In the past two years, you have helped us a lot, without which we couldnt have been made such great progress in English.去掉been6However, its high time that immediate measures must be taken.mustshould