专题08情态动词与虚拟语气（专题）-2017年高考英语考纲解读与热点难点突破

专题08情态动词与虚拟语气（专题）-2017年高考英语考纲解读与热点难点突破

专题08情态动词与虚拟语气（专题）‎ ‎2017年高考英语考纲解读与热点难点突破 ‎【2017年高考考纲解读】‎ 情态动词是各地高考试题中的必考项目，每年高考单项填空必有一道考查情态动词的项目。考点依次是：推测(可能性)→请求/允许→必要性→特殊用法。试题的立意不偏不怪，但有效信息越来越隐蔽，语境越来越真实，考查角度越来越细致，这些因素在很大程度上增加了试题的难度。而虚拟语气的试题偏少，有些省份已将虚拟语气列为不考的项目。‎ ‎【重点、难点剖析】‎ 第一部分、情态动词 一、can/could与be able to ‎1．can/could用来表示“一般能力”；be able to有多种时态，且用来表示在特定条件下的“具体能力”。如：‎ My grandma is over seventy，but she can still read without glasses.‎ They will be able to tell you the news soon.‎ He was able to flee Europe before the war broke out.‎ ‎2．表示允许可用can或could，与may/might意义接近。could可用于现在时，只是语气更加委婉、客气，回答时则一般要用can而不用could。‎ ‎—Could I have the television on?‎ ‎—Yes，you can./No，you can't.‎ 二、may与might ‎1．表示允许，意为“可以，许可”，用法基本上同can与could。如：‎ May I use your bicycle?‎ ‎2．表示可能性，意为“也许，可能”。如：‎ According to the weather forecast, it may rain tomorrow.‎ ‎3．may可以放在句首，表示祝愿。如：‎ May good luck be yours!‎ 三、must与have to ‎1．must用来表示说话人的主观看法；have to表示客观的需要，强调外界压力，不得已而为之。如：‎ He said that they must work hard。‎ 他说他们必须努力工作。(主观上要做这件事)‎ My brother was ill, so I had to call the doctor in the middle of the night.‎ 我弟弟生病了，我只得半夜里把医生请来。(客观上需要做这件事)‎ ‎2．表示“不必”，须用don't have to或needn't。must的否定式表示“禁止，绝对不可”。如：‎ You don't have to tell him about it.‎ 你不必告诉他那件事。‎ You mustn't tell him about it.‎ 你绝不能告诉他那件事。‎ ‎—Must we do it now?‎ 我们必须现在做吗？‎ ‎—No, you needn't.‎ 不，你们不必。‎ 四、shall ‎1．用于第一、第三人称的疑问句中，用来征求对方的意见或请求指示。如：‎ What shall he do next?‎ 他下一步干什么呢？‎ ‎2．用于第二、第三人称的陈述句中，表示说话人的意愿，有“命令、警告、允诺、威胁、强制”等意思。如：‎ He shall stay in bed.‎ 他必须躺在床上。‎ You shall have it back next week.‎ 下周一定还你。‎ He says he won't go, but I say he shall.‎ 他说他不去，但我说他必须去。‎ 五、will与would ‎1．will用于各种人称，表示“意志、意愿”或“决心”等。如：‎ If you will keep your watch half an hour slow, it is hardly surprising that you are late for your appointments.‎ 如果你想要让你的表慢半个小时，你约会时迟到就不足为怪了。‎ ‎2．will表示习惯性的动作，有“总是，惯于”的含义。如：‎ An Englishman will usually show you the way in the street.‎ 英国人通常是会在街上给你指路的。‎ ‎3．would可表示过去反复发生的动作。如：‎ On Sundays he would get up early and go fishing.‎ 星期天他总是早起去钓鱼。‎ 六、should与ought to ‎1．should表示“建议”或“劝告”，有“应该”之意。如：‎ You should learn from each other.‎ ‎2．ought to表示根据某种义务或必要“应当”做某事。如：‎ Everyone ought to obey the traffic regulations.‎ ‎3．should和ought to也可用来表示推测，意为“想必会……”。如：‎ ‎—When can I come for the photos? I need them tomorrow afternoon.‎ ‎—They should be ready by 1200.‎ 七、情态动词表示推测 ‎1．can用于肯定句中表示客观的可能性，意为“有时会”；用于疑问句中可以表示推测，意为“可能”，有时表示一种惊讶的语气；用于否定句中也可以表示推测，can't意为“不可能”，语气很强烈。‎ It is usually warm in my hometown in March, but it can be rather cold sometimes.‎ 我的家乡在三月份通常很暖和，但有时候也会相当冷。‎ Mr. Bush is on time for everything. How can it be that he was late for the meeting?‎ 布什先生做什么事情都很准时，他怎么可能开会迟到呢？‎ ‎—Let's visit Tom together, Stephen.‎ ‎—There's no need to do so. He can't be at home, because I saw him board the flight to Beijing this morning.‎ ‎——Stephen，咱们一起拜访汤姆吧。‎ ‎——没必要这样做。他一定不在家，因为今天早晨我看见他登上了飞往北京的航班。‎ ‎2．may/might用于肯定句中可以用来表示不十分肯定的推测，意为“有可能”；用于否定句中也可以表示推测，may not意为“可能不”，表示一种不太确定的语气。‎ The traffic is heavy these days. I might arrive a bit late, so could you save ‎ me a place?‎ 这些天交通很繁忙，我可能会来晚一点，请你帮我保留个位置好吗？‎ ‎3．must表示推测时只能用于肯定句中，意为“一定，必定”，表示十分肯定的语气(在疑问句中或否定句中要用can/could)。‎ ‎—It's the office! So you must know eating is not allowed here.‎ ‎—Oh, sorry.‎ ‎——这是办公室！所以你一定知道这里不许吃东西。‎ ‎——噢，对不起。‎ ‎4．should用来表示推测时意为“应该”，即含有“按道理来说应当如此”的意思。‎ There shouldn't be any difficulty about passing the road test since you have practiced a lot in the driving school.‎ 因为你在驾校训练了这么多，通过路考应该没什么困难。‎ 八、“情态动词＋have done”结构 ‎1．should/ought to＋have done，表示“过去本应该做而(实际)没有做的事情”，含有责备或遗憾的语气，意为“本应该……”。其否定形式为“should not/ought not to have＋done”，表示某种行为本不该发生但实际上发生了。‎ I shouldn't have watched that movie—it'll give me horrible dreams.‎ 我本不应该看那部电影——它会令我做噩梦。‎ You ought to have come to the party yesterday, but why didn't you come?‎ 昨天你本来应该参加聚会的，可是你为什么不来？‎ ‎2．must＋have done，用于肯定句，表示“过去一定做过某事”，表示一种很有把握的推测。注意，对过去发生的情况的否定推测常用“can't/couldn't＋have done”表示。‎ ‎—Ye Shiwen won two gold medals in London Olympic Games.‎ ‎—She must have gone through tough training.‎ ‎——叶诗文在伦敦奥运会获得了两枚金牌。‎ ‎——她肯定受到严格的训练。‎ ‎—Do you know where David is? I couldn't find him anywhere.‎ ‎—Well. He can't have gone far—his coat's still here.‎ ‎——你知道大卫在哪里吗？我到处找不到他。‎ ‎——大卫的上衣还在这里，因此他肯定没走远。‎ ‎3．needn't＋have done，表示“过去没有必要做某事，但实际上做了某事”。‎ Mark needn't have hurried. After driving at top speed, he arrived half an hour early.‎ 马克本没必要那么匆忙。他以最快速度开车，结果早到了半个小时。‎ ‎4．may/might＋have done，表示对过去情况的一种不太有把握的可能性的推测，表示“可能已做了某事……”，否定句表示“可能还没有……”。‎ Sorry, I'm late. I might have turned off the alarm clock and gone back to sleep again.‎ 对不起，我迟到了。我可能把闹钟关掉后又睡着了。‎ ‎5．could＋have done表示“过去本来可以做某事，但实际上没有做”；can/could＋have done表示“过去可能做了某件事”。‎ I could have saved the poor rabbit, but I didn't have the right drugs with me at that moment.‎ 我本来可以拯救那只可怜的兔子的，可是我当时没有合适的药品。‎ 第二部分、虚拟语气 一、虚拟语气在虚拟条件句中的用法 虚拟情况 从句谓语 主句谓语 例句 与现在事 实相反 过去式 ‎(be用were)‎ would/‎ should/‎ could/might ‎ do If he were here, he might be able to help.‎ What would you do if you were in his place？‎ ‎、与过去事实相反 had done would/‎ should/‎ could/might have done If I had started a little earlier, I would have caught the train.‎ I could have done it better if I had been more careful.‎ 与将来事实相反 过去式 were to do/‎ should do would/‎ should/‎ could/might do If I were to do it, I would do it in a different way.‎ I would certainly go if I had time.‎ ‎1.在具体运用中，条件从句中有时可省略if而采用倒装结构。如：‎ Had it not been for your help, we wouldn't have achieved so much.‎ ‎2．介词without/but for、连词but、副词otherwise常用来表示某种假设条件。如：‎ I wouldn't have made such rapid progress without your help.‎ ‎3．有时候从句动作和主句动作发生的时间不一致，这时谓语动词的形式要根据各自的时间来调整。如：‎ If the weather had been more favourable, the crops would be growing still better.‎ 二、“should＋动词原形”表示的虚拟语气 这一类型常见词有“一坚持(insist)、二命令(order, command)、三建议(advise, suggest, propose)、四要求(request, require, demand, desire)”。以上词及其派生名词所接的名词性从句都使用“(should＋)动词原形”的虚拟语气。‎ ‎①Jane's pale face suggested that she was ill, and her mother suggested that she(should) have a medical examination.‎ 简苍白的脸色表明她病了，她母亲建议她去检查身体。‎ ‎②She insisted that the man had stolen her car and that he(should) be sent to prison.‎ 她坚持说那个男人偷了她的车，并坚决要求他坐牢。‎ 三、特殊句式中的虚拟语气 If only/It's (high) time (that)．..‎ wish/would rather/as if等固定句式要求用相应的虚拟语气表达形式。‎ ‎①I wish I could fly.‎ 真希望我能飞。‎ ‎②I would rather you came tomorrow.‎ 我宁愿你明天来。‎ ‎③If only I had taken your advice!‎ 要是听从了你的建议该多好啊！‎ ‎【题型示例】‎ 题型1、情态动词的基本语法 ‎ ‎【例1】(2016·北京，34)Why didn't you tell me about your trouble last week？If you ________(tell)me，I could have helped.‎ ‎ 【举一反三】(2015·重庆，12改编)You ______ be Carol.You haven't changed a bit after all these years. ‎ 立意与点拨：空后为动词原形，故此处只能填助动词或情态动词；根据下文内容可知此处是说话人的猜测，因为有“据”可循，所以非常肯定，故填语气最为强烈的情态动词must，意为“一定”。 学&科网 答案：must　句意为：你一定是卡罗尔。这么多年后你一点儿都没变。根据语境可知，此处应该用情态动词表示推测，由下文“这么多年后你一点儿也没变”可推知此处为非常肯定的猜测，故填must，意为“一定”。‎ ‎【变式探究】He ________ sleep, although he tried to, when he got on such a hunt for an idea until he had caught it.‎ ‎【答案】couldn't　‎ ‎ 【举一反三】The door ________ open, no matter how hard she pushed.‎ ‎【答案】wouldn't　‎ ‎【解析】本题考查情态动词。句意：无论她怎样用力推，这扇门就是不开。根据句意可知，wouldn't 用于表示过去的否定句中时，表示拒绝，可译为“不肯/愿意，总是不”等。这里门好像有了意愿一样和她作对，这是一种拟人的用法。学&科网 ‎【变式探究】I'm going to Europe on vacation together with John if I ________ find the ‎ money.　　　　　　　　　　　　　　　　‎ A．can B．might C．would D．need ‎【答案】A ‎【解析】句意：如果我现在能有足够的钱，我将和约翰一起去欧洲度假。本题考查情态动词表能力。can能够；might可能；would过去常常，愿意；need需要。‎ ‎【变式探究】 The fire spread through the hotel very quickly but everyone________get out.‎ A．had to B．would ‎ C．was able to D．could ‎【答案】C ‎【解析】考查could和was able to的区别。could表示有某种能力；was able to表示经过努力能够做到，强调成功。句意：大火很快蔓延了整个宾馆，但是大家都成功地离开了。根据语境可知，强调成功地逃出，故选C。‎ ‎【特别提醒】‎ 表示“能力”的情态动词有：can, could, be able to ‎(1)情态动词can只有两种时态形式，现在时can和过去式could, 而be able to有多种时态形式。‎ Mary can play the piano.She has been able to play it since she was five.‎ 玛丽会弹钢琴，她5岁起就会弹了。‎ ‎(2)表示过去能力时，was/were able to表示经过一番努力后取得了成功。相当于manage to do或succeed in doing，而could没有这个含义。‎ Yesterday I was able to get home before the heavy rain.‎ 昨天我在下大雨前赶到了家里。　　　‎ 题型2、情态动词的基本语法------表必要、义务、责任 ‎【例2】—The fire in the supermarket last night was terrible!‎ ‎—They ________ have taken some measures to prevent it occurring. ‎ 立意与点拨：考查“情态动词＋have done”结构。 ‎ 答案：should　句意为：——超市昨晚的火灾很可怕。——他们本应该采取一些措施来预防火灾的发生。这里表示“应该做某事而实际上未做”，所以用should have done结构，故答案为should。‎ ‎【变式探究】One of our rules is that every student ________ wear school uniform while at school.‎ ‎【答案】shall　‎ ‎【解析】考查情态动词的用法。句意：我们有一项规定，每位学生在校期间都要穿校服。此处shall表示按照法律、条例、规定必须要做的事情。‎ ‎【变式探究】 I ________ use a clock to wake me up because at six o'clock each morning the train comes by my house.‎ A．couldn't B．mustn't C．shouldn't D．needn't ‎【答案】D ‎ 【变式探究】 —I don't care what people think.‎ ‎—Well, you________.‎ A．could B．would C．should D．might ‎【答案】C ‎【解析】句意：——我不介意别人怎么想。——噢，你应该那么做。根据语境可知，应选should，意为“应该”，表示一种建议，劝说。‎ ‎【特别提醒】‎ 表示“必要性”的情态动词通常有：must, should, ought to, have to ‎(1)ought to与should意思大体相同，但ought to语气比should重，往往表示从法律或道义上“应该”。‎ You are his father and ought to take care of him.‎ 你是他父亲，应当照顾他。(有责任，从道义上应该)‎ Young people should show respect to the old.‎ 年轻人应该尊重老年人。‎ ‎(2)have to表示“必须，不得不”，这个意义与must很接近，但must表示主观意志，而have to表示由于客观因素不得不做某事。‎ I told her that she must give up smoking.‎ 我叫她必须戒烟。‎ I have to hand in my term paper before 5：00 p．m.today.‎ 我必须今天下午5点前交学期论文。　　　‎ 题型3、情态动词的基本语法------表请求、允许、命令、禁止 ‎【例3】The new law states that people ________ drive after drinking alcohol.‎ A．wouldn't B．needn't C．won't D．mustn't ‎【答案】D ‎【解析】句意：新颁布的法律禁止人们酒后驾车。由题干中的law可知答案为D项。‎ ‎【变式探究】 One of our rules is that every student ________ wear school uniform while at school.‎ A．might B．could C．shall D．will ‎【答案】C ‎ 【变式探究】 —Will you read me a story，Mummy?‎ ‎—OK.You ________ have one if you go to bed as soon as possible.‎ A．might B．must C．could D．shall ‎【答案】D ‎【解析】句意：——妈妈，给我讲个故事好吗？——好，如果你尽快上床睡觉，我就给你讲一个。shall在此处表示“允诺”，故选择D项。‎ ‎【特别提醒】‎ 情态动词“偏义”大本营 (1)表示过去经过努力而成功地做了某件具体的事情时，只能用was/were able to，不用could。‎ (2)must有一种含义，即“偏要”。‎ (3)shall可以用于第二、第三人称，表示说话人的允诺、命令、警告、威胁等；在法律、条约、协定等文件中可以表示义务、规定等。‎ (4)will可以表示意愿。will还可以表示经常性、习惯性、倾向性等，意为“经常，惯于，总是”。‎ (5)should表示惊异、意外等情绪，经常用于疑问句和肯定句中，多译为“竟然，居然”。　　　‎ 题型4、情态动词的基本语法------表肯定推测 ‎【例4】(2016·浙江，17)George can't ________(go)too far.His coffee is still warm.‎ ‎【答案】have gone　【解析】句意：乔治不可能走得太远了。他的咖啡仍然是温的。can't have done是对过去的否定推测。学&科网 ‎ 【举一反三】(2015·四川，2改编)You________be careful with the camera.It costs! ‎ 立意与点拨：根据空后的动词原形be可知此处填情态动词，根据句意和后面的感叹号可知这是说话人提出的要求，且语气非常强烈，因此只能填must。 ‎ 答案：must　句意为：你必须要小心使用相机。它很贵重！根据下文的It costs！可知，此处是说话人对使用相机的人提出的要求，must意为“必须”，表示说话人主观上的要求，语气强烈。‎ ‎【变式探究】 It ________ be the vocabulary that caused you the problem in the exercise because you know a lot of words.‎ ‎【答案】couldn't　‎ ‎ 【举一反三】—What are you doing this Saturday?‎ ‎—I'm not sure, but I ________ go to the Rolling Stones concert.‎ ‎【答案】might/may　‎ ‎【解析】考查情态动词。句意：“你这个周六做什么？”“我不确定，但是我或许会去滚石演唱会。”根据答语的前半句“我不确定”可知，空格处应填表示“可能，或许”意思的词语。‎ ‎【变式探究】—Good morning.I've got an appointment with Miss Smith in the Personnel Department.‎ ‎—Ah，good morning.You ________ be Mrs.Peters.‎ A．might B．must C．would D．can ‎【答案】B ‎【解析】第一个说话人说和史密斯小姐有约，那下面的人就回应说，“那您一定就是Mrs.Peters了”，因此排除A、C、D。‎ ‎【变式探究】What do you mean，there are only ten tickets?‎ There ________ be twelve.‎ A．should B．would C．will D．shall ‎【答案】A ‎【解析】你这是什么意思，只有十张票吗？应该有十二张。should表示“应该，应当”。‎ ‎【变式探究】 Some people who don't like to talk much are not necessarily shy；they ________ just be quiet people.‎ A．must B．may C．should D．would ‎【答案】B ‎【解析】言语不多的人未必就腼腆，他们可能只是好静而已。must肯定；may或许；should应该；would想必。‎ ‎【特别提醒】‎ ‎1．must用于肯定句，表示较有把握的推测，意为“准是，一定”。‎ ‎2．should用于肯定句中，语气次之，意为“很可能，应该”，指按常理推测。　　　‎ ‎3．can用在肯定句中，表示理论上的可能性。如：‎ Smoking can cause cancer.‎ 吸烟有可能引起癌症。‎ ‎4．may用在肯定句中，表示对现在把握不大的推测，意为“也许，可能”。‎ ‎5．could，might也可表示推测意义，常用在过去时态中；但在某些场合下，为了使语气更缓和、更委婉，常用could，might代替can，may。如：‎ They saw something in the sky last night.It could/might be a UFO.昨天晚上他们看见天空中有个东西。它有可能是不明飞行物。‎ 题型5、情态动词的基本语法------表推测的用法否定与疑问推测 ‎【例5】 —I don't really like James.Why did you invite him?‎ ‎—Don't worry.He ________ come.He said he wasn't certain what his plans were.‎ A．must not B．need not ‎ C．would not D．might not ‎【答案】D ‎【解析】根据he wasn't certain可知，James可能不来。学&科网 ‎【变式探究】 —How's your new babysitter?‎ ‎—We ________ ask for a better one.All our kids love her so much.‎ A．should B．might C．mustn't D．couldn't ‎【答案】D ‎【解析】考查情态动词的用法。句意：——你的新保姆怎么样？——找不到更好的了。我们的孩子们很喜欢她。should应该；might可能，可以；mustn't禁止；couldn't不可能。根据句意选D。‎ ‎【变式探究】—________it be Tom that stole the manager's mobile phone?‎ ‎—No. As far as I know, Tom is very honest.‎ A．May B．Can C．Must D．Should ‎【答案】B ‎ 【特别提醒】‎ ‎1．否定推测 ‎(1)表示否定的推测时，can't/couldn't语气最强，指“不可能”，带有惊异、怀疑的感情色彩。如：‎ The story sounds reasonable，but it can't be true.‎ 这个故事听起来合情合理，但不可能是真的。‎ ‎(2)语气不很肯定时，常用may not或might not表否定推测，意为“可能不，也许不”。如：‎ He may not/might not be at home.他可能不在家。‎ ‎2．疑问句中的推测 疑问句中的推测，常用can或could，意为“可能”。如：‎ Who can it be？Can it be Jenny?‎ 那能是谁呢？是玛丽吗？‎ ‎3．情态动词表推测的三种时态 ‎(1)对将来情况的推测，用“情态动词＋动词原形”。‎ She must arrive before 5. 5：00前她一定到。‎ ‎(2)对现在或一般情况的推测，用“情态动词＋be”，“情态动词＋be doing”或“情态动词＋动词原形”。‎ He must/may be listening to the radio now.‎ 他一定/可能正在听收音机。　　　‎ 题型6、虚拟语气在条件中的运用 ‎【例6】(2016·浙江，15)________(have)the governments and scientists not worked together，AIDSrelated deaths would not have fallen since their highest in 2005.‎ ‎【答案】Had　【解析】句意：如果政府和科学家不共同努力，与艾滋病相关的死亡就不会从2005年的最高点下降。这是一个省略了从属连词if的虚拟语气句，使用了倒装句式。根据主句的would not have fallen可知，这里是表示过去的虚拟语气，所以用had。‎ ‎ 【举一反三】(2015·天津，13改编)I wish I________(be) at my sister's wedding last Tuesday，but I was on a business trip in New York then. ‎ 立意与点拨：利用虚拟语气考查时态。 ‎ ‎ 【变式探究】 I should not have laughed if I ________(think) you were serious.‎ ‎【答案】had thought　‎ ‎【解析】考查虚拟语气。句意：如果我早知道你是认真的，我原本不该嘲笑你的。主句中谓语动词使用should not have laughed，表明与过去的事实相反，从句应该使用had done。‎ ‎【举一反三】If we ________(book) a table earlier, we wouldn't be standing here in a queue.‎ ‎【答案】had booked　‎ ‎【解析】考查虚拟语气。句意：如果我们早订张桌子的话，我们就不会站在这儿排队了。根据语境可知，此处是if引导的虚拟条件句，从句叙述的是与过去事实相反的情况，因为“我们没有早订桌子”，谓语动词用had done；而主句叙述的是与现在事实相反的情况，“现在我们正站着排队”。 学&科网 ‎【变式探究】Sorry，I am too busy now.If I ________ time，I would certainly go for an outing with you.‎ A．have had B．had had C．have D．had ‎【答案】D ‎【解析】句意：对不起，我现在太忙了。如果我现在有时间的话，我会和你一起出去郊游。根据句意以及句中的now可知，此处表示对现在情况的一种假设，所以从句中谓语动词要用过去式，而主句用“could/would/should/might＋动词原形”。‎ ‎【变式探究】 Maybe if I ________ science，and not literature then，I would be able to give you more help.‎ A．studied B．would study C．had studied D．was studying ‎【答案】C ‎【解析】考查错综时间的虚拟语气。主句用的是would be able to...表示对现在情况的假设，但由if从句中的then可知，从句表示对过去情况的虚拟，故用had studied。‎ ‎【变式探究】 This printer is of good quality.If it ________ break down within the first year，we would repair it at our expense.‎ A．would B．should C．could D．might ‎【答案】B ‎ 【误区警示】‎ ‎1．误用情态动词 例1、John，look at the time. ________ you play the piano at such a late hour? ‎ 易错警示：此题易误填need需要。解此题时要注意语境，体会语气。 ‎ 答案：Must　句意：约翰，看看时间。这么晚了你偏要弹钢琴吗？从说话人的语气判断，含有不满之意。must在此表示特定的语气和态度，意为“偏要，硬要”。‎ 例2、I ________ have been more than six years old when the accident happened. ‎ 易错警示：此题易误填mustn't。mustn't意为“一定不能，被禁止”，不能与have done连用。 ‎ 答案：couldn't　句意：在事故发生时我不可能超过6岁。shouldn't have done表示“本来不该做而实际上却做了”，needn't have done表示“本来不必做而实际上却做了”，均不符合题意。‎ ‎2．虚拟语气 例3、________it snow, the crops would grow better. ‎ 易错警示：与将来事实相反的虚拟语气，if从句中情态动词只用should，不用would，might，will。 ‎ 答案：Should　句意：如果下雪的话，这些庄稼会长得更好。本题考查与将来事实相反的if条件句，if从句的谓语动词形式为：①过去式；②should＋动词原形；③were to＋动词原形。‎ 例4、The little boy handles the vase as if it ________(be) made of steel. ‎ 易错警示：as if(as though)用在虚拟语气中： ‎ ‎(1)如果as if引导的从句谓语动词与主句谓语动词所表达的动作同时发生，as if引导的从句谓语动词用过去时。 ‎ He looks as if he were an artist。‎ 他看起来像个艺术家。 ‎ ‎(2)如果as if引导的从句谓语动词所表达的动作先于主句谓语动词所表达的动作，as if引导的从句谓语动词用过去完成时。 ‎ She speaks English so fluently as if she had studied English in America. ‎ 她英语说得很流利，好像在美国学过似的。‎