寒假总动员）2015年高三英语寒假作业 专题06 情态动词和虚拟语气（学）情态动词和虚拟语气情态动词主要用来表示说话人的情感、态度等，是中学英语语法的重点，也是高考的热点，是单项填空和语法填空中必考的一个知识点情态动词在高考中主要考查四点：情态动词表示推测和可能性的用法；情态动词与虚拟语气；情态动词表达“情感、态度、语气等”，情态动词表示 “必要性”等方面的用法重点知识整合】 一、情态动词 1．shall (1)表示命令、许诺、警告、强制、威胁、决心等，一般用于第二、三人称中，并用于陈述句 You shall have my answer tomorrow.（允诺） 你明天就会得到我的答复 He shall be sorry for it one day,I tell you.（警告） 我告诉你，他总有一天会后悔的 You shall do as I tell you.（命令或吩咐） 你应该按照我告诉你的去做 (2)shall用于第三人称，表示“应，必须” Those belonging to our club shall wear uniforms. 我们俱乐部的成员应该穿统一制服。
(3)用于征求对方的意见和指示，用在第一、三人称的疑问句中 Shall I turn on the light?我能打开灯吗？ Shall he come to see you? =Do you want him to see you? 你愿意他来看你吗？ 2．will (1)表示意志、愿望或决心等 --Can someone help me?有人能帮帮我吗？ --I will.我来帮你 (2)与you连用，表示请求 Will you come this way，please?你能走这条路吗？ (3)表示规律性的“注定会” People will die without air or water. 离开水或空气人们将会死的 (4)表示习惯或特征 This old man is very strange. He will sit for hours without saying anything．这位老人很怪，他会坐在那儿几小时不说话 3．should与ought to should(1)表劝告、建议时常作“应当”讲，与ought to有时可互换，ought to更注重责任和义务。
(2)表示预测可能性，并意为“可能，（按道理）应该” They should be here now．他们现在应该在这儿 (3)用于委婉、谦逊地提出意见或建议 I should think you are right．我以为你是对的 ought to (1)ought to表示应该，语气比should强 We ought to help each other in our work. 在工作中我们应该互相帮助 (2)ought to表示按照责任、义务等该做的事 You're my father, so you ought to look after me. 你是我父亲，因此你应该照顾我 (3)ought to表示非常可能的事 He ought to know her address．他应该知道她的地址 (4)ought(not)to have done与should(not)have done的用法相同4.would 与used to (1)两者都可表示过去重复的习惯 (2)used to强调过去的行为同现在的对比，而would则单纯表示过去的习惯动作，常与often，every day等状语连用。
He used to be a very strong man. 他以前是个身体很强壮的人现在体质差多了） We would sit in the yard every evening and listen to his sto ry. 我们过去每天晚上坐在院子里听他讲故事过去重复性行为）． (3)表示过去的状态，只能用used to，不能用would There used to be a temple at the foot of the mountain. 以前山脚下有座庙 5．need和dareneed和dare既可用作情态动词，也可用作实义动词，用作情态动词时，主要用于否定句和疑问句，用作实义动词时，可用于各种句式 Need I come?我有必要来吗？ 一No,you needn't(don't have to).／Yes,you must. 不，你没有必要／是的，你必须来 You needn't telephone him now. 你现在不必给他打 He didn't dare to go home．他不敢回家。
None of them dared to mention this. 他们谁也不敢提这件事注意：need问句的肯定回答用must，否定回答用needn't或don't have to 6．must与have to (1)must表示说话人的主观看法，have to往往强调客观需要 (2) must一般只表示现在，have to则有更多的时态形式 (3)二者否定意义不同，mustn't表示“禁止” (4)询问对方意愿时，应用must —— Must I clean all the rooms?我必须打扫所有房间吗？ —— Yes, you must./No, you don't have to/needn't. 是的，你必须／不，不必了 (5)二者的用法口诀： “主观职责”说“必须”， must赶紧用上去； 若是环境“不得不” 赶快换用have to You mustn't go你不能去 You don't have to go．你不必去7．can与be able to(1)can只用于一般现在时和一般过去时(could)，be able to可用于更多时态中。
2)can只表示具备了某种能力，但不一定做了，而be able to指过去某时设法做成了某事，was/were able to do相当于managed to do或succeeded in doing.I talked with her for a long time, and eventually I was able to make her believe me．我跟她谈了很久，最终还是使她相信了我的话My father could speak English．我父亲会说英语3)在否定句中或与感官动词连用时，could与was/were able to可通用 I could/was able to see them through the window. 透过窗子我能看到它们I wasn't able to/couldn't catch the last train.我没能赶上最后一列火车 8．情态动词表推测(1)肯定句中，can可以表示客观的（理论上的）可能性，并不涉及具体的某事是否会发生，此种用法常常可以用来说明人或事物的特征；要表达具体某事实际发生的可能性时，不可用can，须用could，may，might。
Accidents can happen on such rainy days.这种下雨的天气可能会发生事故客观的可能性）Peter may go with us tonight,but he isn、t sure yet.彼得今晚可能和我们一起去，但他还没确定实际可能性，不用can)We may go camping next Sunday.下星期日我们可能去野营实际可能性）(2)表示推测的情态动词层次比较 词形 肯定式 否定式 疑问式must 必定，必然 / will 很可能，大概 不会，不该 会……吗would可能性比will小语气比won't弱 语气比will弱should 确定或可能有的 未来或期待 / /ought to总应该，理应(含义同should) /can / 不可能 有可能吗could 可确定的可能 不可能 语气比can弱may或许，也许，也说不定 可能不 /might 比may还弱比may not还弱 /注意：①表推测时，may，must常用于肯定句，一般不用于否定句和疑问句。
may not表示“可能不”；如果表达否定意义“不可能”或疑问意义，用can/could的适当形式 --Are you coming to Jeff's party?你会来杰夫的晚会吗？ --I'm not sure.I might go to the concert instead. 我不确定我可能去听音乐会作为代替 Mr. Bush is on time for everything. How can it be that he was late for the opening ceremony?布什先生做事守时出席开业庆典他怎么会迟到了呢？ （2）would，could，should，might并不一定与过去时间有关，而表示其可能性弱于它们相应的现在时形式 This can't be done by him.这不可能是他做的 This may not be done by him.这可能不是他做的 Can this be done by him?这可能是他做的吗？ This could/may/might be done by him. 这件事可能是他做的。
He should be around sixty years old.他可能60岁左右了 ③should表推测时，表示确定或可能有的未来或期望 It's nearly seven o'clock. Jack should be here at any moment.快7点了杰克随时都可能在这里 --When can I come for the photos?I need them tomorrow afternoon．我什么时候可以来取照片？我明天下午就要用 ——They should be ready by 12：00．它们12点就能（洗）好了9．表示“宁愿做某事”的句式：would rather do sth. (than do sth.)would do sth. rather than do sth.would rather sb. did sth.10．情态动词+ have done prefer to do sth."prefer to do sth. rather than do sth. prefer doing sth. to doing sth. 情态动词十完成式 用法 例句must have done表示对过去已经发生的行为进行推测，意为“想必／准是／一定做了……”。
I didn't hear the telephone;I must have been asleep.我没有听到响，我一定是睡着了can have donecan't have done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He can't have studied English before.他以前不可能学过英语Can he have gone to his aunt's?他可能到他姑妈家去了吗？ could have donecouldn't have done用于肯定句中，表示“有可能已经……”，还可以表示过去没有实现的可能性，意为“本来可以……”用于否定句，表示“不可能”He could have walked to the station~it is so near.他本该走着去车站的，这么近I couldn't ha,~e won,so I didn't go in for the race.我不可能获胜，因此我没参赛may/might have done表示对过去已发生的行为的推测，意为“也许已经……”，一般只用于肯定句和否定句中，不用于疑问句，用might则表示语气更加不肯定。
He may not have finished the work.他可能还没有完成工作She might have caught a cold.她可能感冒了might have done表示“本可能……”，但实际上没发生的事He might have given you more help,even though he was very busy．他本来可以给你更多的帮助，即使他非常忙should/ought to + have done用于肯定句时，表示“本该做……”，而实际上未做；用于否定句时，则表示不该做的事反而做了 The tree is dead.r should have given it more water.这棵树死了我本该多给它浇点水的（但没有）Tom,ought not to have told me your secret.汤姆本不该把你的秘密告诉我（但他告诉了）needn't have done表示做了本来不必去做的事，注意didn't need to do表示“没必要做而实际上也没有做某事”I needn't have bought the book.我本来没有必要买这本书（却买了）。
I didn't need to clean the windows. My brother did it.我没有必要擦窗子，我弟弟做这事了二、情态动词的一些习惯用法 (1) cannot.., too/enough表示“无论怎么……也不过分……”“越……越好”You cannot be too careful.你越小心越好You cannot remember enough English words.你记的英语单词越多越好 (2)cannot but do sth.表示“不得不／只好做某事” I cannot but admire your bravery.我不得不佩服你的勇气 (3)may well和may as well结构“may well+动词原形”是一种常用结构，意为“完全能，很可能”，相当于to be very likely to. He may well be proud of his son.他完全可以为儿子感到自豪may as well十动词原形”意为“最好，满可以，倒不如”，相当于had better do或have no strong reason not to do,You may as well do it at once．你最好马上就做这件事。
三、虚拟语气 1．虚拟语气在条件从句中的用法 情况 虚拟条件句 主句与现在事实相反过去式(be一律用were)与将来事实相反过去式(be一律用were) should+动词原形 were to+动词原形would/should/could/might +动词原形与过去事实相反 had+过去分词would/should/could/might+ have+过去分词If she knew English,she wouldn't ask me for help.如果她懂英语的话，她不会找我帮忙的 If I had known her number,I would have called her.如果我知道她的号码的话，我就给她打了If it were to snow this evening,they would not go out.如果今晚下雪，他们将不出去了注意： (1)错综时间条件句有时主句与从句的动作发生在不同时间，这时主句和从句谓语动词的虚拟语气形式必须因时间不同而不同。
If she hadn't trained so hard, she wouldn't be able to run so fast.（从句与过去事实相反，主句与现在事实相反）如果她以前训练没有这么刻苦的话，她现在不可能跑得那么快If he had died in the accident,he couldn't stand in front ofyou now.如果他在那次事故中死去了，他现在就不会站在你面前了 (2)省略if的用法如果条件句的从句部分含有were，should或had，有时可将if省略，把were，should或had移到句首 Were I you, I would get up early in the morning.如果我是你的话，我早晨就会早起 Had you arrived at the station ten minutes earlier yesterday,you could have caught the train. 昨天如果你早到车站10分钟的话，就会赶上火车了 Should it rain,the crops would be saved. 要是下雨的话，庄稼就会有救了。
(3)含蓄条件句：句中没有明显的虚拟条件句，而是用其他手段来暗示存在虚拟条件有以下情况： ①通过介词短语with，without, but for，but that等 Without air,there would be no living things.若没有空气，就没有生物 But for your mother's help we wouldn't have finished the work.要不是你妈妈帮忙，我们不可能完成这项工作 ②通过连词or, but，though，once等 I would have attended the meeting, but I have been too busy.我本来要参加会议的，只是太忙了 ③通过不定式短语 You would be a fool to refuse his offer.要是你拒绝他的提议，那就太傻了 ④通过分词短语 Given more attention, the trees could have grown better.倘若给予更多关心，这些树木本来可以生长得更好。
⑤无词语暗示条件 Such mistakes could have been avoided.这些错误本来是可以避免的2．宾语从句中的虚拟语气 (1)表示命令、建议、要求等一类的动词，如order，suggest，propose, insist, require, demand, advise, request等后接的宾语从句中，谓语动词要用“should+动词原形”，should可以省略 We suggested that the meeting (should) be put off.我们建议把会议推迟 I required that he (should) come to my office.我要求他到我的办公室来 He insisted that you (should) be seated there.他坚持让你坐在那儿注意：suggest与insist①当suggest不表示“建议”而是表示“暗示”“认为…可能…,使人联想起”讲时，从句中的谓语动词要用陈述语气 Her expression suggested (that) she was angry.她的表情表明她生气了。
②当insist表示“坚持说、强调”之意时，用陈述语气 He insisted that he was better．(insist在此表示“坚持说、坚持认为”)他坚持说他好些了 He insisted that Tom had stolen his horse. 他坚持认为汤姆偷了他的马 (2)wish后的宾语从句中：一般过去时——与现在事实相反的愿望，过去完成时——与过去事实相反的愿望，would/could+动词原形——将来难以实现的愿望I wish you had come to the lecture.但愿你当时听报告了I wish I could fly to the moon some day.如果有一天我能飞到月球上去就好了3) would rather的从句后面用一般过去时表示将来或现在，用过去完成时表示过去I would rather you told me the truth.我宁愿你告诉我真相了I would rather you had returned the book yesterday.我真希望你昨天已经把这本书还了3．名词性从句中的虚拟语气 (1)虚拟语气用于主语从句在主语从句中，谓语动词的虚拟语气用“(should+)动词原形”的结构，表示惊奇、不相信、惋惜、理应如此等。
①It is necessary/important/natural/strange that... (should)do… ……做……是必要的／重要的／自然的／奇怪的It is necessary that you (should) clean the room after work．你在工作后打扫房间是有必要的It is very strange that he (should) have left without saying good-bye．他离开时没有说再见是很奇怪的②、It is desired/suggested/decided/ordered/requested/proposed that... (should) do... 据请求／建议／决定／指示／要求／建议……（应该）做……It is ordered that the cloth (should) be woven right now.据指示，现在就应纺织布料 (2)虚拟语气用于表语从句和同位语从句在advice, idea, order, demand, plan, proposal, suggestion,request等名词后的表语从句和同位语从句中，其谓语动词要用虚拟语气的结构“(should+)动词原形”。
My idea is that we (should)do exercises first.我的观点是我们应该先做练习Our suggestion is that the meeting should be held at once.我们的建议是会议应立刻召开An order came that we (should) start at once.命令传来我们应立刻出发4．as if/as though从句中的虚拟语气由as if /as though(好像)引导的从句，谓语动词用过去式或过去完成时表示虚拟语气It seems as if it were spring already.现在仿佛已是春天了He talked as if he had been to Paris.他谈起来好像他去过巴黎She looks as though she had known all the secrets.她看上去像是已经知道了全部秘密注意：as if/as though可引导可能是事实的从句，常用在系动词look，seem，taste，sound等词后It looks as if it is going to rain．仿佛要下雨了。
5．其他句型中的虚拟语气 (1)if only句型（要是……该有多好） If only I could see him now!要是我现在能看到他该有多好啊！ If only I knew the answer.要是我知道答案就好了 If only I hadn't lost it．要是我没有弄丢它就好了 (2)It is (high) time that后面的从句的谓语动词要用过去式或用“should+动词原形”，但should不可省略 It is time that we planted trees there. 是我们到那儿种树的时候了 It is high time that we should plant trees there.早该是我们到那儿种树的时候了。