专题 3 情态动词和虚拟语气
◆情态动词的核心考点 1．can，be able to 和 could (1)can 和 be able to 都表示能力，意思上没多大区别。但 can 只有现在和过去时，而 be able to 则有更多的形式。但当成功地完成某一具体动作时，通常不用 could 而用 was/were able to 来 表示。这时 was/
were able to 相当于 managed to，表示经过一番努力，终于能够完成某事。 Her mother can speak French. The wounded man was still able to get to the village and was saved by the villagers in the end. (2)表示猜测“可能”，一般用于疑问句和否定句。 —Can the news be true? —It can’t be true. Someone is knocking at the door.Who could it be? (3)can 可以表示理论上的可能性，指常有的行为或情形，意为“有时会……”。 Anybody can make mistakes. (4)表示请求、允许(表请求时，口语中常用 could 代替 can 使语气更委婉，回答时用 can)。 Can I go now? —Could I come to see you tomorrow? —Yes，you can.(否定答语可用 No，I’m afraid not.) (5)表示惊异、怀疑、不相信的态度(主要用于否定句、疑问句或感叹句中)。 How can that be true？I can’t believe my eyes and ears. How could you be so careless? (6)can 的特殊用法。 can but 只有；can’t but 不得不；can’t...too 再怎样也不为过，越……越好 I can but wait. I can’t but wait. You can’t be too patient to the customers. 2．may 和 might 的用法 (1)表示允许、请求，might 比 may 的语言更委婉一些。 —May I watch TV now? —Yes，you may.(Yes，please.) —No，you mustn’t.(No，you’d better not.) (2)表示可能性时，might 比 may 的可能性小，may 表示的可能性比 can 小(主要用于陈述句、 肯定或否定句，疑问句用 can 代替)。 The story may not be true. (3)表示祝愿(不用 might) May you succeed! (4)may/might as well 最好还是……，不妨 You might as well do it now. (5)may/might well 很可能 He may well be late for class.
3．must，have to 和 ought to 的用法 (1)must ①表示“必须，应该，一定要”。强调主观看法，只有现在时形式，否定式是 must not(mustn’t)。 must 开头的问句，其否定回答要用 needn’t 或 don’t have to 代替。 ②表示必然的结果。 All men must die. ③还可表示主语固执、偏要做他人不希望做的事。 It can’t help；he must do that. (2)have to 着重客观需要，能用于更多时态(过去时或将来时)。 He will have to be there before ten. (3)ought to 表示义务和责任，“应该”，比 should 语气要强。 You ought to take care of yourself. 4．need 和 dare 的用法 (1)need 表示“需要，必要”，只能用于否定句和疑问句。在肯定句中，常用 must 和 have to 代 替。 (2)dare 表示“敢”，通常用于否定句、疑问句和条件状语从句中。 Dare you go home alone at eleven in the evening? (3)need 和 dare 的特殊用法 ①need 表“需要”时，可用 want，require 代替。 The desk needs to be repaired./The desk needs repairing. ②dare 作实义动词时，在肯定句中要接 to，在疑问句和否定句中 to 可省去。 He dares to catch a snake. I do not dare (to) complain. Do you dare (to) swim in the river? 5．will 和 would 的用法 (1)will ①表示请求、建议，常用于第二人称。 Will you please go with me? ②表示意愿、决定、允许。 I will never do that again. ③表示习惯性动作或某种倾向，“总是，惯于”，通常用于第三人称。 Rosa will always be late for school. (2)would ①表示请求、建议，比 will 委婉，指现在时间，多用于第二人称。 Would you like a cup of tea? ②表示过去习惯性动作或某种倾向。 We would play badminton on Sundays. 6．shall 和 should 的用法 (1)shall 用于第一、三人称，在问句中表示征求对方意见或请求。 Shall I come in? 用于第二、三人称的陈述句中，表示命令或威胁。 You shall do as your father says. (2)should
①表示责任、义务，意为“应该”。 ②表示惊讶语气，意为“竟然”。 You should wear slippers in class. ③用于条件句，表示“假如，万一”，省去 if，should 可提至句首。 Should you be late，apologize to the teacher. 7．情态动词表示推测或判断的用法 下表即是表示推测的情态动词使用的场合： 情态动词 must may/might can/could 对现在和未 来的推测 must＋do may/might＋do can/could do 用来表示一种估计的情况 “ 按 理 会 / 估 计 会 ”should do 对过去 的推测 must have done may/might have done can/could have done 使用场合 肯定句 肯定句、否定句 否定句、疑问句(could 可 用于肯定句) 肯定句、否定句、疑问句
should have done
情态动词＋have done 的用法 (1)should have done 表示“本来应该做某事而实际上未做”， 而 shouldn’t have done 则表示“本不 应该做某事而实际上做了”。 You should have told me about it earlier. You shouldn’t have said such words to your parents. (2)ought to have done 也表示“本应该……”，而 ought not to have done 则意为“本不应该……”。 You ought to have told me about it earlier. You ought not to have said such words to your parents. (3)needn’t have done 表示“本无必要做某事而实际上做了”。 You needn’t have walked so quickly since time was enough. (4)could have done 表示“本来有可能……而事实上未做到”。 I could have come on time，but my car broke down on the way. (5)may/might have done 表示“过去可能发生过某事”或“本来应该或可以做某事(实际上没做)”。 You might have given him more help，but you were so busy. ◆虚拟语气的核心考点 1．虚拟语气用于条件状语从句 (1)表示与现在事实相反的假设，条件状语从句中的谓语动词用一般过去时(be 动词用 were)， 而主句中的谓语动词用“would/should/could/might＋动词原形”。 If I were you，I would buy that house. If he had time，he should go with you. (2)表示与过去的事实相反，条件状语从句中的谓语动词用过去完成时，主句中的谓语动词则 用“would/should/might/could＋have＋过去分词”。 If he had taken my advice，he would have succeeded in passing the examination. (3)表示与将来事实相反，条件状语从句中的谓语动词用一般过去时或“should/were to＋动词 原形”，而主句中的谓语动词则用“would/should/could/might＋动词原形”。 If it were to rain tomorrow，the football match would be put off. (4)当条件状语从句表示的行为和主句表示的行为所发生的时间不一致时，动词的形式要根据 它所表示的时间作相应调整。
If they had worked hard，they would be very tired now.(从句说的是过去，主句指的是现在) 2．虚拟语气用于名词性从句 (1)虚拟语气在宾语从句中的运用。 ①“wish＋宾语从句”表示不能实现的愿望，译为“要是……就好了”等。表示现在不能实现的 愿望，从句中的谓语动词用一般过去时；表示将来不能实现的愿望，从句中的谓语动词用 “would/could＋动词原形”；表示过去不能实现的愿望，从句中的谓语动词用“had＋过去分词” 或“could/should＋have＋过去分词”。 I wish it were spring all the year round. I wish I had known the answer. I wish I could fly like a bird. ②在表示建议、要求、命令等动词后的宾语从句中，谓语动词用“should＋动词原形”，should 可以省略。 常见的动词有：suggest，advise，propose，demand，require，insist，request，command，order 等。 She suggested we (should) leave here at once. The doctor ordered she should be operated on. (2)虚拟语气在同位语从句和表语从句中的运用。 表示建议、 要求、命令等的名词， 如 advice，idea，order，demand，plan，proposal，suggestion， request 等，其后的表语从句和同位语从句中谓语动词用“(should＋)动词原形”，should 可以省 略。 His suggestion that we (should) go to Shanghai is wonderful. My idea is that they (should) pay 100 dollars. (3)虚拟语气在主语从句中的运用。 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、理 应如此等。 It is necessary (important，natural，strange，etc.)that we (should) clean the room every day. It was a pity (a shame，no wonder，etc.)that you (should) be so careless. It will be desired (suggested，decided，ordered，requested，proposed，etc.)that she (should) finish her homework this afternoon. 注意：这种从句表示的是事实。如果人对这种事实表现出惊奇的情感，就可用虚拟语气；反 之，如果不表示惊奇等情感，that 从句也可用陈述句语气。 It is a pity that you can’t swim. 3．虚拟语气在其他场合的运用 (1)虚拟语气在 as if/as though， even if/even though 等引导的表语从句或状语从句中， 如果从句 表示的动作发生在过去，用过去完成时；指现在状况，则用一般过去时；指将来状况则用过 去将来时。 He did it as if he were an expert. Even if she were here，she could not solve the problem. (2)虚拟语气用于定语从句中。 这种从句常用于句型“It is (high)time (that)．..”中，定语从句的谓语动词用一般过去时(be 用 were)或“should＋动词原形”，意为“(现在)该……”。 It’s time that I picked up/should pick up my daughter. It’s high time we were going/should go. (3)虚拟语气用在 if only 引导的感叹句中。
If only I were a pilot. If only I had taken his advice. (4)虚拟语气在一些简单句中的运用。 ①情态动词的过去式用于现在时态时，表示说话人谦虚、客气、有礼貌或语气委婉，常出现 在日常会话中。 It would be better for you not to stay up too late. Would you be kind enough to close the door? ②用于一些习惯表达法中。 Would you like a cup of tea? I would rather not tell you.
◆情态动词、虚拟语气与语法填空 对于情态动词在语法填空中考查主要注意情态动词的一般用法以及“情态动词＋have done”； 而对于虚拟语气的考查除了注意情态动词的选用，还需注意一般过去时与过去完成时在虚拟 语气中的考查。 典题试做 1 在空白处填入适当的情态动词或括号内所给动词的正确形式 1．You be Carol.You haven’t changed a bit after all these years.(2015·重庆) 答案 must 解析 根据 be 动词为原形， 可判断此处缺少情态动词或助动词。 根据后句 You haven’t changed a bit 可知，说话者完全认出了 Carol，猜测的语气非常肯定，故填 must。 2．You feel all the training a waste of time，but I’m a hundred percent sure later you’ll be grateful you did it.(2015· 陕西) 答案 may 解析 由句中的 but 及后一分句中的 a hundred percent sure 可知， 此处表示语气不强烈的推测， 故填 may。 3 ． Although you find bargains in London ， it’s not generally a cheap place to shop.(2014· 大纲全国) 答案 can 解析 由语境可知，此处表示“你可能在伦敦找到便宜货”，指客观上的可能性。故填 can。 4．Mum：Are they there? Oh，my goodness.I have put them in there when the phone rang.(2014· 新课标全国样卷) 答案 must 解析 动词原形前常跟情态动词或助动词。根据句意，是对过去的推测，故肯定句中用 must have done 形式。 5．—Sorry，Mum! I failed the job interview again. —Oh，it’s too bad.You have made full preparations.(2015·福建) 答案 should 解析 表示“本应该做某事，但事实上却没有做”，用 should have done sth.表示，故填 should。 6．I still remember my happy childhood when my mother take me to Disneyland at
weekends.(2014· 四川) 答案 would 解析 由主句中的关键信息 my happy childhood 可知，是小时候经常被带去迪斯尼乐园。表 示“过去常常”要用情态动词 would。 7．He walked in as if he (buy) the school.And the word quickly got around that he was from New York City.(2012· 广东) 答案 had bought 解析 这是由 as if 引导的虚拟语气，因为是与过去事实相反，故用过去完成时。 8．No one be more generous；he has a heart of gold.(2013· 天津) 答案 can/could 解析 “No one could be more generous”是否定词和比较级连用，表达最高级含义，can/could 可以在否定句中表示推测。 9．Ellen is a fantastic dancer.I wish I (dance) as well as her.(2015· 陕西) 答案 danced 解析 wish 后跟宾语从句时，从句中需要用虚拟语气，主句用一般现在时，从句中用 did 表 示对现在事实的虚拟。故填 danced。 10．It is lucky we booked a room，or we (have) nowhere to stay now.(2015· 安徽) 答案 would have 解析 or 引导含蓄虚拟条件句，or 后面是主句，相当于 if we hadn’t booked a room，we would have nowhere to stay now，根据“now”可知，是对现在进行虚拟。故填 would have。 应对策略 1 1．若句中谓语动词为原形，在其前设纯空格题时，注意考虑情态动词与助动词。然后根据句 意或句式结构填入恰当的情态动词或助动词。 2．一旦判断所给动词在句中作为谓语后，就考虑其时态、语态、语气、主谓一致等。注意虚 拟语气中的时态， 除了 if 虚拟条件句， 还应注意虚拟语气的标志词， 如： suggest， would rather， as if，wish，otherwise，or，but for 等。 ◆情态动词、虚拟语气与短文改错 情态动词与虚拟语气在短文改错中偶有考查。 常考查情态动词后的动词形式错误或 be 动词遗 漏；情态动词混用或虚拟语气中情态动词以及时态的错用。 典题试做 2 单句改错(每小题 1 处错误) 1．If you are me，would you talk to them？(2015· 四川) 答案 are→were 解析 此处是虚拟语气，表示与现在情况相反，所以要把 are 改为 were。 2．We must found ways to protect our environment.(2015· 全国Ⅰ) 答案 found→find 解析 考查情态动词的用法。情态动词后面要接动词原形。 3． Thank you for all you have done for me.Mom， though I may often say it， I do love you.(2012· 四 川) 答案 may 后加 not 解析 根据句意，应为“尽管我可能不经常说，但是我真的很爱您”。 4．My punishment lasted a year.Meanwhile，I found out that with more patience I must make my toys last.My attitude changed from then on.(2012· 新课标全国) 答案 must→could/might
解析 must 必须，一定，用在此处语境不合适。句意为：同时，我发现耐心一些，我可以让 我的玩具玩得更久些，所以应用 could/might。 5． I have been practising for three weeks now， but I still couldn’t get used to it—in fact， I’ve nearly killed three people.(2010· 四川) couldn’t→can’t 应对策略 2 做此类改错题时，需注意以下几个方面： (1)看句中情态动词是否运用正确； (2)看是否考查虚拟语气；若是考查虚拟语气，注意分清主句与分句中的时态关系以及不同句 式中的虚拟语气构成形式。 ◆书面表达中情态动词与虚拟语气易错点聚焦 1．表达的单调性 例如在写一封回信向好友表达建议时，重复使用 You should...既显得单调，同时强硬的语气 影响了交际效果。 我们可以灵活多样地表达建议，如 You’d better.../You might as well.../Why not...？等。 2．情态动词搭配错误 (误)You’d not better quarrel with your neighbors whatever happens. (正)You’d better not quarrel with your neighbors whatever happens. —Need I tell him everything that has happened to his father? (误)—Yes，you need. (正)—Yes，you must. (误)The King was so hottempered that no one dared tell him the bad news. (正)The King was so hottempered that no one dare (dared to) tell him the bad news. 3．时间错综句的虚拟语气的表达错误 从句与主句或上下文所表达的时间不一致，部分考生仍照搬某种形式，因未按照句中所表述 的时间关系，而用错虚拟形式。如： (误)If his television set had not been stolen yesterday，he would have watched TV now. (正)If his television set had not been stolen yesterday，he would watch TV now. (误)If I were you，I wouldn’t miss the film last night. (正)If I were you，I wouldn’t have missed the film last night. (误)If she comes tomorrow，I would tell her the news. (正)If she came tomorrow，I would tell her the news. (正)If she should come tomorrow，I would tell her the news. (正)If she were to come tomorrow，I would tell her the news. (误)If only she didn’t miss the train the other day. (正)If only she hadn’t missed the train the other day. (误)It’s time that they go home. (正)It’s time that they went/should go home. (误)Without your help，we didn’t make so much progress. (正)Without your help，we wouldn’t have made so much progress. (误)If she didn’t miss the train，she is here now. (正)If she hadn’t missed the train，she would be here now.
Ⅰ.单句语法填空 1．When I was a child，I watch TV whenever I wanted to. 答案 could 解析 根据空后 watch 可知，该空应填情态动词 could 意为“可以，能够”。 2．If we (book)a table earlier，we couldn’t be standing here in a queue. 答案 had booked 解析 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， 谓语动词用 had done。 3． If he had spent more time practising speaking English before， he (be) able to speak it much better now. 答案 would be 解析 句意为“如果以前他花更多时间练习说英语的话，现在他英语就会说得好多了”。由从 句中的 had spent 可知从句与过去事实相反；由主句中的 now 可知主句与现在事实相反，故 用 would be。 4．I would rather that they (come) here tomorrow. 答案 came 解析 根据语境“我宁愿他们明天来”可知他们已经来过了，而这与说话人的意愿不符，表示 将来的愿望，要用过去时，故填 came。 5．My mom suggests that we eat out for a change this weekend. 答案 should 解析 suggest 表示“建议”时，所跟宾语从句要用虚拟语气，用 should do 构成。 6．Grace doesn’t want to move to New York because she thinks if she (live) there，she wouldn’t be able to see her parents very often. 答案 were to live/should live/lived 解析 Grace 不想搬到纽约去，因为她认为如果她住在那里，就不能经常见到父母了。考查 虚拟语气。根据 wouldn’t be able to see...及句意可知，该句为与将来事实相反的虚拟语气，所 以 if 从句谓语动词需用“were to＋do 或 should＋do 或动词过去式”。 7．Don’t handle the vase as if it (make) of steel. 答案 were made 解析 考查虚拟语气。as if 意为“好像”，分析句意可知 as if 后面的句子须使用虚拟语气，并 且所述情况是对现在事实的假设，因此使用一般过去时的被动语态。 8．We lost our way in that small village，otherwise we would (visit) more places of interest yesterday. 答案 have visited 解析 考查虚拟语气。根据语境可知谓语动词部分所表达的意思与过去事实相反，需用 “should/would/could/might＋have＋过去分词”结构。 9． Sorry， I am too busy now.If I (have) time， I would certainly go for an outing with you. 答案 had 解析 考查虚拟语气。 根据第一句可知设空处是对现在的假设， 故 if 从句谓语动词为过去式。 10．Jack is a great talker.It’s high time that he (do) something instead of just talking.
答案 did/should do 解析 考查虚拟语气句型 It is high time that sb.did sth.或 It is high time that sb.should do sth.到 某人该做某事的时候了。 Ⅱ.单句改错(每小题 1 处错误) 1．Judging from what you say，he ought succeed. 答案 ought 后加 to 2．I would rather I stayed at home yesterday. 答案 stayed 前加 had 3．I can have lent you the money.Why didn’t you ask me? 答案 can→could 4．Something is wrong with my computer and it need repairing. 答案 need→needs 5．I asked him whether he needs go there. 答案 needs→need 6．I would rather to work than play. 答案 去掉 to 7．You’d better to wear rubbers，for it’s raining outside. 答案 去掉 to 8．She could sang very well when she was a girl. 答案 sang→sing 9．It is high time that we take some measures to protect the wild animals. 答案 take→took 或 take 前加 should 10．Was I to be a teacher in the future，first of all，I would try my best to give students lessons. 答案 Was→Were Ⅲ.语法填空 A(情态动词和虚拟语气专练) Lucy is an outgoing lady.She 1.can play many kinds of musical instruments.Actually，she 2.could play the piano when she was 8 years old.Lucy also keeps taking exercise every day.She says that she has to do some sports because she 3.must keep slim.“You 4.shall get fat soon if you don’t take exercise every day.” She usually says to her friends. As for her， an elegant lady should try to keep fit.However， last week， she found that she 5.might put on weight and her husband suggested that she 6.should lose weight.And these days she’d rather that she 7.took(take) more exercise every day.However，she is always lack of time because she ought to take care of her children. One night after supper，she walked quickly in order to go dancing at the Tomorrow Park and she was late.On her way， she thought that the dancing must 8.have begun(begin)， and the coach 9.could have taught or shown many new moves.She was afraid that her friends might 10.have left (leave) before she got there.She was regretful then. She 11.should have had supper earlier，or she could have taken a taxi，and indeed she needn’t 12.have taken(take) a bath in advance.When she reached the park finally，she found nobody was there.She remembered suddenly that it had been reported on the radio that there would be a heavy rain that night. B Reading books is a good hobby for all kinds of reasons.
First，reading books 13.is(be) fun.You can always keep yourself 14.interested(interest) and it can help you have an enjoyable time if you like reading.This is especially useful when the weather is bad.It is a 15.relaxing(relax) hobby too. Next， you can read a book anywhere： in a car， in a waiting room， on a plane， in bed—even in the bath.16.What/All you need is a book! Reading is a convenient hobby as it is easy to stop and then start again. Another good reason for reading books is 17.that it is useful.If you read as a hobby，you 18.will get(get) better and better at it.This means that you will read faster and will become 19.better(good) at understanding what you read.As your reading improves， you will probably find your school work becomes much easier.Many school subjects depend 20.on good reading and，as you read you learn more and more. Good readers are most likely to be good 21.writers(write) ， too.They are usually good at 22.spelling(spell) as well，and have more things to write about.Reading books is really a wonderful hobby.
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