第七讲 情态动词和虚拟语气
一、情态动词的基本用法
情态动词 用 法 例 句
(1)表示禁止(用于否定句)。 You mustn’t park here！It’s an emergency exit.
(2)表必要性意为“必须”。 —Shall I inform him of the change of the schedule right now?must，in case he comes late for the meeting.
(3)表示偏执固执意为“非得偏要”。 If you must gountil the storm is over.
can和(1)表示“能力”。 —No one can be compared with Yao Ming in playing basketball. (2)表示惊讶常用在否定句和疑问句中。 How could you do such a silly thing？
(3)表示礼貌地请求别人做某事意为“能可以”。 —This dish is really delicious.Could you please say it in Chinese?
(4)cannot...too/
enough表示“无论……也不过分”；“越……越好”。 You can’t be too careful while driving. (1)用于第一、第三人称疑问句中表示说话人征求对方的 Shall I go out for a walk after supper?
(2)用于第二、第三人称陈述句中表示说话人给对方的命令、警告、允诺或威胁。 —Will you read me a storyshall have one if you go to bed as soon as possible.
may和(1)may和might表示“许可”、“可能性”、“祝愿”等意义。 —May I take this book out of the reading room? (2)“may as well＋动词原形”意为“最好倒不如”。 If you think the price of beef is too highmay as well buy some pork.It depends on you.
will和would (1)表示意志、意愿和决心。 ①—Why didn’t you come to Simon’s party last night?would not let me out so late at night.
②I have told him again and again to stop smoking，but he will not listen.
(2)will可以表示一种习惯的动作有“总是”或“总要”之意。 Every morning he will have a walk
(3)would可以表示过去的习惯动作比used to正式但没有“现已无此习惯”的含义。 When we worked in the same firm several years agowould often go to the cinema together.
1．(2017·高考北京卷)________ I have a word with you? It won’t take long. B．Must解析：选A。考查情态动词。句意：我能和你说句话吗？不会花费太长时间的。can“能够”用于含第一人称的问句中(Can/Could I．..？)表示请求和许可；must“必须”；shall用于第一人称的问句中(Shall I/we...)用于提建议或要求他人作决定should“应该”。根据have a word with you可知此处是在请求对方允许。(2017·高考江苏卷)It was sad to me that they________ bring me food.
A．mightB．would
C．shouldD．could
解析：选C。考查情态动词。句意：他们自己那么穷should可以用在that引导的从句中跟在某些形容词或动词之后表示“竟然居然”带有惊讶的语气。故选C项。might可能或许可以；would(过去)总是愿意；could能够或许。(2017·高考重庆卷)I’ve ordered some pizza________ worry about cooking when we get home tired.
A．can’t B．dare not解析：选C。考查情态动词的基本用法。句意：我已经要了一些比萨因此当我们疲惫不堪地到家时不必担心做饭的事情。can’t“不能”；dare not“不敢”；needn’t“不必”；may not“可能不”。根据前一分句I’ve ordered some pizza(我已经要了一些比萨)可知已经准备好了吃的东西所以没有必要(needn’t)担心(cooking)做饭的事C项符合语境。二、情态动词表推测
情态动词 用 法 例 句
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.(1)can用于肯定句中表示客观的可能性意为“有时会”；(2)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；(3)用于否定句中也可以表示推测意为“不可能”语气很强烈。 ①It is usually warm in my hometown in Marchcan be rather cold sometimes.
②Mr.Bush is on time for everything.How can it be that he was late for the meeting?
③(2017·高考安徽卷)It couldn’t be the vocabulary that caused(1)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”；(2)用于否定句中也可以表示推测意为“可能不”表示一种不太确定的语气。 (2017·高考北京卷)—You needn’tmight do.
should 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.
1．(2017·高考江西卷)Life is unpredictable; even the poorest ________ become the richest.解析：选D。考查情态动词。句意：生活是不可预料的甚至最贫穷的可能变成最富有的。根据unpredictable(不可预料的)可知本题应该选might(可能)。(2017·高考天津卷)No one ________be more generous; he has a heart of gold.must
C．dare
D．need
解析：选A。句意：没人比他更慷慨；他有一颗金子般的心。“No one could be more generous”是否定词和比较级连用表达最高级含义项could可以在否定句中表示推测为正确答案。B项表推测只用在肯定句中和need不符合句意。三、情态动词＋have done
情态动词＋用 法 例 句
表示对过去已经发生的行为进行推测意为“一定做了某事”。 Harry is feeling uncomfortable.He
must have drunk too much at the party last night.
may/might表示对过去已发生行为的推测意为“也许/或许已经(没有)……”。一般用于肯定句或否定句中。 Sorrymight have turned off the alarm clock and gone back to sleep again.
can...have
done/cannot
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。(can换成could时语气较委婉) ①I can’t find him anywhere.Where can he have gone?can’t have finished reading the book so soon because it is difficult even to an adult.
could have
done 本来能够而没有做 (2017·高考福建卷)He could have gone on regretting it, 表示本来可能……但实际上没有发生的事情。 You should not swim in that sea.You might have been eaten by a shark.
should/ought(1)用于肯定句时表示本该做某事而实际上未做；(2)用于否定句时则表示不该做的事反而做了。 ①You shouldn’t have done it so carelessly.ought to have returned the book earlier.
③You ought not to have refused his offer.
needn’t
have done 表示做了本来不必去做的事没必要做而做了”。温馨提示 didn’t need to do表示“没必要做而实际上也没有做某事”。 ①You needn’t have brought the book because Tom has one here.didn’t need to buy the dictionary.I had a copy at home.
(2017·高考陕西卷) My book________ have taken it?
A．needB．must
C．shouldD．could
解析：选D。考查“情态动词＋have done”的用法。句意：我的书《哈迪斯之屋》不见了。会是谁把它拿走了呢？need have done sth.本来有必要做某事而没做；must have done sth. 一定做过某事只用于肯定句中表示非常肯定的推测；should have done sth.本来应该做某事但实际上没做。根据句意D项could。
一、if条件从句中的虚拟语气
类 型 用 法 例 句
引导的条件从句 与现在事实相 从句谓语动词：过去式(be用were)主句谓语动词：should/would/could/might＋动词原形 Sorry, had time, I would certainly go for an outing with you.
很抱歉我现在非常忙。若我有时间我将一定与你外出郊游。
与过去事实相反 从句谓语动词：had＋过主句谓语动词：should/would/could/might＋have＋过去分词 (2017·高考北京卷)If we had booked a table earlieruldn’t be standing here in a queue.
如果我们早订张桌子的话我们就不会站在这儿排队了。
与将来事实相反 从句谓语动词：过去式/were＋不定/should＋动词原形主句谓语动词：should/would/could/might＋动词原形 Grace doesn’t want to move to New York because she thinks if she were to live there, wouldn’t be able to see her parents very often.
Grace不想搬到纽约因为她想如果要是住那里她将不可能经常地见到她的父母。
引导的条件从句的倒装 如果在表示虚拟语气的条件句中含有were或should可将if省略然后将were或should移至主语之前。 Had we made a great effort we might have succeeded.(＝If we had made a great effort...)要是我们付出巨大的努力也许我们已经成功了。
混合条件句的虚拟语气 有时条件句的动作与主句动作发生的时间不一致这时动词的形式应根据它们表示的时间加以调整。 (2017·高考天津卷)If he had spent more time practising speaking English beforewould be able to speak it much better now.
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。
1．(2017·高考北京卷)We __________ back in the hotel now if you didn’t lose the map.解析：选D。考if非真实条件句用一般过去时态主句用“would/could/should/might＋动词原形”。故选D项。2．(2017·高考湖南卷)If Mr. Dewey ________ present解析：选B。考查虚拟语气。句意：要是杜威先生当时在场的话他就会给那儿的人提供任何可能的帮助。根据本句中的he would have offered可知这里是表示与过去事实相反的虚拟语气所以从句应用过去完成时。与过去事实相反的虚拟语气的句子结构是：主句谓语用 “would/could/ should/might have done”had done。(2017·高考福建卷)________no modern telecommunicationsrom around the world.
A．Were thereB．Had there been
C．If there areD．If there have been
解析：选A。考查虚拟语气中的倒装句。句意：要不是现代化的电讯我们就不得不等好几个星期才能得到来自世界各地的消息。根据主句中的关键词would have to以及句意可知这是一个与现在事实相反的虚拟语气从句应用一般过去时即if there were...。当if从句中有weread或should时可将if省略同时将were或should提到主语前构成部分倒装所以选A项。二、虚拟语气在名词性从句中的应用
类 型 用 法 例 句
宾语从句 后接的从句中动词为“(should＋)动词原形”。 Teachers recommend parents not allow their children under 12 to ride bicycles to school for safety.
wish后的从句中的谓语可用一般过去时、过去完成时和should/would＋动词原形它们分别表示与现在、过去和将来情况相反。 —How much of the foreign expert’s speech have you understood?had worked harder at English.
主语从句 在“It is necessary/important/strange/suggested/demanded/ordered/requested＋that从句”中从句中的谓语动词用should＋动词原形。 ①It is strange that such a person should be our friend.(should) be put off till next week.
表语从句和同位语从句 在suggestion等名词后的表语从句和同位语从句中要用虚拟语气其构成是“should＋动词原形”可以省略。 ①My idea is that we (should) think it over before accepting it.②We all agreed to his suggestion that we (should) go to Dalian for a visit.
1．(2017·高考浙江卷)Eye doctors recommend that a child’s first eye exam ________ at the age of six months old.解析：选B。句意：眼科医生建议孩子第一次视力检查应该在六个月大的时候进行。recommend建议后接宾语从句时从句用虚拟语气谓语动词用should do形式ld可以省略所以正确答案为B项。(2017·高考陕西卷)My mom suggests that we________eat out for a change this weekend.解析：选A。句意：我妈妈建议这个周末出去吃饭换换口味。suggest作“建议”讲其后宾语从句要用虚拟语气也就是从句中的谓语部分要用should do形式可以省略；另外要注意的是suggest作“表明”这一含义讲时其后宾语从句不用虚拟语气。三、其他句型中的虚拟语气
类 型 用 法 例 句
(high) time
(that)．..句型中谓语动词用一般过去时或should＋动词原形。 Jack is a great talker. It’s high time that he did/should do something instead of just talking.
would rather would rather所接的从句中的谓语动词用一般过去时(对现在虚拟)或者过去完成时(对过去虚拟)。 I would rather you stayed at home now.
后面的谓语动词常用一般过去时(对现在虚拟)、过去完成时(对过去虚拟)与过去将来时(对将来虚拟)表示强烈的愿望。 If only our dream had come true！
as if as if引导的状语从句中动词可以用过去时或过去完成时表示虚拟。 Don’t handle the vase as if it were made of steel.
(2017·高考陕西卷)We would rather our daughter ________ at home with usB．has stayed解析：选C。考查虚拟语气。句意：我们宁愿我们的女儿和我们一起待在家里但是那是她的选择她已经不再是一个小孩子了。would rather后接that从句时要用虚拟语气如果与现在或it is her choice可以判断这件事情还没发生因而从句用一般过去时所以选择C项。四、含蓄条件句的虚拟语气有时假设的情况并不以条件从句表示而是由otherwiset，or，without，but for等来引导。would have come sooner but I didn’t know that they were waiting for me.
我本该早一些到但我不知道他们在等我。
1．(2017·高考安徽卷)People are recycling many things which they ________ away in the past.解析：选D。考查虚拟语气。本题难度较大因为其中的虚拟条件是通过语境“People are recycling many things”含蓄表达的。根据in the past可知这里说的是过去的情况对过去情况的推测或评说应使用“情态动词＋完成式”。本题句意是：现在人们回收利用很多东西而过去他们会将这些东西扔掉。故选D项。(2017·高考浙江卷)They were abroad during the months when we were carrying out the investigation________ to our help.
A．would have come B．could come
C．have comeD．had come
解析：选A。考查虚拟语气。句意：我们进行调研的那几个月期间他们出国了要不然的话他们就会来帮助我们了。由关键信息or可知此处是隐含的虚拟条件句or相当于 if they hadn’t been abroad。这是在叙述与过去事实相反的情况因此这里谓语动词用would have done故A项正确。(2017·高考安徽卷)I________ to my cousin’s birthday party last night解析：选D。句意：昨晚我本应该去参加我堂妹的生日聚会但我没有空。I was not available表示的是过去的真实情况为一含蓄条件相当于if I had been available(如果我有空的话)此处为与过去情况相反的虚拟语气主句应使用“would/might/could/should＋have done”结构故选D项。
1．—________you talk with your mouth full of food，Jack?
—Oh，I’m terribly sorry，but...
A．Will B．Shall解析：选C。考查情态动词。句意：——Jack你非要满嘴食物讲话吗？—why)must you...？表示“(为什么)你非要……？”为固定用法。(2017·四川成都四校联考)I don’t believe he________the task on his own last night.He is such a lazy boy!解析：选C。考查情态动词。后面强调“他”是个懒惰的男孩子故他不可能自己完成了任务。could have done表示“可能干了某事”否定式表示“不可能干了某事”。(2017·湖南株洲三校一模)The giant panda looks very mild. But it ________ be very fierce when you annoy it.解析：选C。考查情态动词。情态动词can在此意为“有时可能会”表示偶尔的可能性。句意：这只大熊猫看起来很温顺。但如果你把它惹怒了它有可能非常凶猛。4.(2017·湖南湘南五校联考)—Mike failed the English exam again. Don’t you think he ________ have spent more time in studying English?
A．mustB．can
C．mightD．should
解析：选D。考查情态动词。句意：——Mike英语考试又没有及格。——你还能指望什么？难道你不认为他应该花更多的时间学习英语吗？should have done表示“本来应该做某事但实际上并未做”符合题意。(2017·合肥一中、安师大附中等六校联考)—Could you give me a ride to the railway station？I’m going to be late.________be in time for the train.
A．shallB．can解析：选A。考查情态动词。句意：——你能开车送我去火车站吗？我要晚了。shall可以用于第二、三人称表示允诺、命令、警告、威胁等语气。________have taken my raincoat with me.
A．couldn’tB．needn’t
C．wouldn’tD．mustn’t
解析：选B。考查情态动词。句意：昨天是个好天我本不该带雨衣。needn’t have done sth.“本不该做某事”符合句意。(2017·四川三校联考)Studying abroad________be stressfult the same time.
A．canB．need
C．mustD．should
解析：选A。考查情态动词。because引导的原因状语从句的内容可知出国学习可能会很压抑。can用于肯定句中意为“可能会”。(2017·四川南充名校模拟)When you arrive at the front door________ open with a touch of your finger.
A．must B．might
C．need
D．will
解析：选D。考查情态动词。句意：你到前门时不需要钥匙因为用手指一碰门就会开了。will在此表示“会”。(2017·重庆联合测试)If you had listened to me, ________at the party. Move over. I’ll drive.
A．areB．were
C．would beD．would have been
解析：选C。句意：要是当初你听我的那么我们现在就在聚会现场了。你挪过去我来开车。if从句表示与过去事实相反的假设而本空表示与现在的实际情况相反的假设说话人此时还在路上因此选C项。(2017·安徽合肥四校高三联考)Had it not been for the postal strike, ________ been held up.
A．might not haveB．should not have
C．must not have
D．may not have
解析：选A。考查虚拟语气。句意：如果不是邮政罢工我寄出的那封家书也不会被耽搁。由“had it not been for...”可看出邮政罢工发生在过去因此家书寄出后被耽搁也发生在过去。might not have done表示对过去事情的虚拟假设意为“原本不可能做某事”。2017·杭州五校第一次联考)—But for your timely warning________ into great trouble.
—Well, you know we’ re friends.
A．would get
B．must have got
C．would have got
D．can’ t have got
解析：选C。考查虚拟语气。句意：——要不是你及时提醒我们也许已经陷入麻烦中了。——好了你知道我们是朋友啊but for意为“要不是如果没有”后接名词相当于一个if条件句根据句意可知本题中if条件句与过去事实相反即if you hadn’t warned us此时主句谓语动词应用would have done表虚拟。(2017·温州适应性测试)—I think Tom should have invited Mary to the party.________．解析：选C。考查虚拟语气和省略。句意：——我认为汤姆本应该邀请玛丽来参加晚会的。——这和我们无关。如果汤姆打算邀请她的话他早就做了。根据语境可知此处是和过去事实相反的虚拟语气故主句用would/could/might have done形式且此处的助动词have不能省略故C项正确。________to reduce the pollution in our hometown.
A．was madeB．be made
C．will be made D．would be made
解析：选B。考查虚拟语气。desire后的宾语从句及所在句子中的名词性从句均应使用虚拟语气虚拟形式为“should＋动词原形”其中should可省略故选B项。(2017·湖南湘南五校联考)It is required that the new employees________safety training before they start to work.C．be provided
D．shall be provided
解析：选C。考查虚拟语气。动词requireshould＋)动词原形”。employees和provide之间存在被动关系故用被动形式。句意：根据要求雇员在上岗前应给予他们安全培训。________it.
A．haven’t seen B．hadn’t seen
C．didn’t seeD．don’t see
解析：选B。考查虚拟语气。wish后的宾语从句中需用虚拟语气。此处是与过去事实相反的愿望从句用过去完成时。