2017高考英语一轮语法对点讲练：4 情态动词和虚拟语气

　　语法对点讲练四　情态动词和虚拟语气

　　一、情态动词

　　知识点讲解

　　情态动词本身有一定的词义，但需和其他动词一起构成谓语。除have to, be able to外，情态动词无人称和数的变化。除have to, be able to外，情态动词只有现在时和过去时两种基本形式。除ought, used外，情态动词后面接不带to的不定式。情态动词中have to可以用have got to代替；need, dare也可用作实义动词；used to有两种否定形式：used not to和did not use to。

　　1．can, could

　　①表示具有某种能力，指有能力做某事。could表示过去的能力。

　　②表示请求和允许，和may相近；口语中可用could表示委婉语气，但回答时仍用can。

　　③表示可能性，常用于否定句和疑问句中。

　　④表示惊异、怀疑、不相信的态度。

　　特别提示　

　　⑤“can not/never ... too/enough”表示“无论怎么……也不过分；越……越好”。

　　You can't be too careful when travelling alone.

　　⑥cannot but do sth.表示“只好；不得不”。

　　Father cannot but agree with his daughter's opinion.

　　⑦can't help doing sth.表示“禁不住做某事”。

　　2．be able to

　　⑧be able to可以有多种时态，如：将来时(will be able to)，完成时(have/has/had been able to)。

　　⑨be able to侧重通过努力成功做成某事的能力。

　　He said he could swim across the river.(指本身具有这种能力)

　　At last he was able to swim across the river.(指通过努力做到了)

　　3．may, might

　　⑩表示允许、许可或征求允许，否定回答时要用mustn't。might比may语气委婉。

　　表示可能性，might比may可能性更小。

　　may表示祝愿、愿望，常用于感叹句。

　　特别提示　

　　may/might as well do sth.“不妨；还是……为好”。

　　Everything is ready. We might as well start now.

　　4．will, would

　　表示意志、决心或愿望。

　　用于第二人称，表示请求、建议等。

　　will表示“总是；惯于”。would表示过去的习惯，意为“过去常常”。

　　表示推测或猜想。

　　用于否定句，表示“不肯；不乐意”。

　　特别提示　

　　表示功能、特性，意为“能；行”，多用于否定句。

　　The door won't open.

　　would表示提出想法，通常与like, love, hate, be glad, prefer, be happy等连用。

　　5．shall

　　用于第一、三人称的疑问句中，表示征求对方的意见或请示。

　　用于第二、三人称的陈述句，表示说话者的命令、警告、许诺等语气。

　　用于第三人称，在条约、规定、法令等文件中表示义务或规定，意为“应；必须”。

　　6．should, ought to

　　表示应该，常用于表示现在或将来的责任或义务；还可表示推测，指有一定依据的推测。

　　should还可表示惊讶，意为“竟会；居然”。

　　It's strange that he should be absent.

　　7．must, have to

　　must强调主观看法，表示必须，have to强调客观需要，意为“不得不”。

　　We must finish this work now.

　　We will have to reconsider this plan.

　　must表示“偏要；非得”等含义。这种用法常用于疑问句、条件句中。

　　Must you waste so much time?

　　must的否定形式mustn't意为“不许；禁止”；若表示“没有必要；不必”时，用needn't或don't have to。

　　must表示推测时，仅用于肯定句，但在反意疑问句中，其后面反问部分取决于must后面的动词形式。

　　You must be a newcomer, aren't you?

　　8．need

　　表示“需要；必须”，常用于疑问句和否定句中。肯定回答用must，否定回答用needn't。

　　9．dare

　　主要用于否定句、疑问句以及条件句中，有过去式形式dared。

　　10．used to

　　“过去常常”，含有今昔对比的意味，表示过去习惯的动作或状态现在已结束。而would表示过去反复发生的动作，但不含对比意味。

　　11．had better, would better

　　had better表示“最好……”； would better表示“宁愿；宁可”。

　　12．情态动词＋have done

　　must have done用在肯定句中，表示对过去情况的肯定推测，语气坚定。

　　can't have done表示对过去情况表示否定的推测，是must have done的否定形式。

　　could have done用于肯定句，表示过去本能完成但事实上并没有完成，意为“本来能够”。

　　may/might have done表示过去“可能发生”某事，意为“可能……；或许……”。

　　should have done表示“过去本应该做某事而没有做”。

　　shouldn't have done sth.表示“过去本不该做某事而做了”。

　　needn't have done表示“过去本没有必要做某事而做了”。

　　对点训练

　　完成下列小题，并指出考查上述哪个知识点(①～)

　　第一组　单项填空

　　1．(2017·新课标卷Ⅰ)The door ________ open, no matter how hard she pushed.

　　A. shouldn't

　　B. couldn't

　　C. wouldn't

　　D. mightn't

　　答案　__C__　知识点　____

　　解析　句意：不管她怎么用力推门，都无法打开这扇门。shouldn't“不应该”； couldn't“主观的不能”； wouldn't“不会；不能(客观)”； mightn't“可能不”。

　　2．(2017·新课标卷Ⅱ)Since nobody gave him any help, he ________ have done the research on his own.

　　A. can B. must

　　C. would

　　D. need

　　答案　__B__　知识点　____

　　解析　句意：由于没人给予他任何帮助，他一定是独立做的研究。must have done对过去的肯定推测。

　　3．(2017·北京卷)— You needn't take an umbrella. It isn't going to rain.

　　— Well, I don't know. It ________ do.

　　A. might

　　B. need

　　C. would

　　D. should

　　答案　__A__　知识点　____

　　解析　句意：——你不必带伞，天不会下雨。——哦，我不知道。天也许会下雨。might“也许”，表推测，符合句意。

　　4．(2017·安徽卷)It ________ be the vocabulary that caused you the problem in the exercise because you know a lot of words.

　　A. may

　　B. couldn't

　　C. should

　　D. needn't

　　答案　__B__　知识点　__③__

　　解析　由you know a lot of words可知不可能是词汇导致的问题。couldn't“不可能”。

　　5．(2017·湖南卷)He ________ sleep, although he tried to, when he got on such a hunt for an idea until he had caught it.

　　A. wouldn't

　　B. shouldn't

　　C. couldn't

　　D. mustn't

　　答案　__C__　知识点　__①__

　　解析　根据“尽管他努力了，但是他不能入睡……”，故用couldn't。

　　第二组　语法填空

　　6．Jack, it's too hot here. ________ I open the window?

　　答案　Shall　知识点　____

　　解析　shall用于第一、三人称疑问句时，用于征求对方的意见。

　　7．If the wound ________ become infected, do not hesitate to call me.

　　答案　should　知识点　____

　　解析　should可以用于条件状语从句中表示事件发生的可能性，意为“假定要；将要”。

　　8．According to his will, his money ________ be used to build a school instead of a market.

　　答案　shall　知识点　____

　　解析　shall用于第三人称，表示依照遗嘱、规章、法律等“必须；应该”怎么样。

　　9．It was very kind of you to do the washing­up, but you didn't ________ do it.

　　答案　have_to　知识点　____

　　解析　句意：你真是太好了，把这些东西洗了，但是你没有必要洗的。didn't have to do表示“本没必要做”，客观上的“不必要”，动作已经发生了。

　　10．— Alice looks sad. Did you tell her about her brother's accident?

　　— Sorry, I ________ (not, tell) her just before her final exams.

　　答案　shouldn't_have_told　知识点　____

　　解析　shouldn't have done sth.表示“本不该做某事，但是已经做了”，含有责备的意味。正确答案是D项。

　　第三组　单项填空

　　11．— How can I achieve my goal?

　　— You ________ work hard and stick to it.

　　A. can

　　B. may

　　C. must

　　D. would

　　答案　__C__　知识点　____

　　解析　must“必须；应该”，表示强烈的劝告。

　　12．(2017·漳州七校5月联考)When we worked in the same office, we ________ have coffee together.

　　A. might

　　B. should

　　C. could

　　D. would

　　答案　__D__　知识点　____

　　解析　would表示过去习惯性的动作，强调过去动作的经常性。

　　13．(2017·甘肃三模)You were stupid to try climbing up there. You ________ yourself.

　　A. can kill

　　B. might have killed

　　C. might kill

　　D. must have killed

　　答案　__B__　知识点　____

　　解析　might have done sth.表示“过去有可能发生某事”，符合句意。must have done sth.表示对过去情况的肯定推测，意为“一定是；准是”。

　　14．(2017·石家庄二模)He ________ it on schedule, but somehow he fell behind.

　　A. must have done

　　B. might finish

　　C. could have finished

　　D. could finish

　　答案　__C__　知识点　____

　　解析　由句意可知，他没有能够完成。could have done sth.表示“本来能够做某事，而没做成”，有责备的含义，符合句意。

　　15．(2017·烟台5月练习三)The weather turned out fine; I ________ have taken the raincoat with me.

　　A. wouldn't

　　B. couldn't

　　C. mustn't

　　D. needn't

　　答案　__D__　知识点　____

　　解析　天气很好，所以本没有必要带雨衣。needn't have done sth.表示“没有必要做某事却做了”，符合句意。

　　第四组　语法填空

　　16．________ we go to the McDonald's? I am sick of the food there!

　　答案　Must　知识点　____

　　解析　must可以用来表示说话人不耐烦，意为“非要；偏偏”，往往暗示令人不愉快的事将要发生。

　　17．You ________ (not) trust an online shop just because it has a beautifully­designed website.

　　答案　shouldn't　知识点　____

　　解析　句意：你不应该只是因为一个网店设计漂亮就轻易相信它。must有些绝对。

　　18．The bike under the tree ________ belong to Peter. Look! His bag is on it.

　　答案　must　知识点　____

　　解析　根据“Look! His bag is on it.”可知树下那辆自行车一定是彼得的。must用于对现在情况的肯定推测。

　　19．Days later, my brother called to say he was all right, but ________ (not) say where he was.

　　答案　wouldn't　知识点　____

　　解析　句意：几天之后，我哥哥打电话报了平安，但不愿说他在什么地方。wouldn't“不愿意；坚决不”，符合句意。

　　20．I ________ (not) thank you too much for all your help to my son while we were away from home.

　　答案　can't　知识点　__⑤__

　　解析　句意：我们不在家时，你对我儿子的帮助，我怎么感谢你都不过分。can't/couldn't ... too ...意思是“再……都不为过”。

　　21．— Did you punish him for losing your digital camera?

　　— Yes, but I don't think I ________ (do) that.

　　答案　should_have_done　知识点　____

　　解析　句意：——他丢了你的数码相机，你惩罚他了吗？——是的，但是我现在认为本不该这样做。答语是一个否定前移的句式， shouldn't have done表示做了不该做的事。

　　22．— The work will take me another week. I'm really tired.

　　— I think you ________ as well consult an experienced worker.

　　答案　may/might　知识点　____

　　解析　句意：——这项工作还得用一周才能完成，我真的太累了。——我觉得你倒不如找一个有经验的工人商量一下。may/might as well表示“还是……的好；倒不如”，相当于had better。

　　二、虚拟语气用于从句

　　知识点讲解

　　1．虚拟语气用于if条件从句

　　①表示与现在事实相反的假设，从句谓语动词用一般过去时(be动词一律用were)。主句谓语动词用should/would/could/might＋动词原形。

　　②表示与过去事实相反的假设，从句谓语动词用过去完成时，主句谓语动词用should/would/could/might＋have done。

　　③表示与将来事实相反的假设，从句谓语动词用过去时，或were to＋动词原形，或should＋动词原形，主句谓语动词用would/could/should/might＋动词原形。

　　特别提示　

　　④错综时间条件句：条件从句与主句谓语动词不是同时发生。谓语动词要根据各自的时间来确定。

　　If I

　　at school, I ， too.

　　If it

　　much, the crops would .

　　If

　　today, we

　　to Beijing.

　　⑤含蓄条件句：由介词with, without, but for, in that position等，或由连词or, otherwise, and, but, but that等代替if条件句。

　　I couldn't have finished the work on time without your help.

　　But for your timely warning, we would have got into great trouble.

　　⑥省略if的虚拟条件句：当虚拟条件句的谓语动词含有were, should, had时，if可省略，而将were, should, had等词置于句首，形成倒装。

　　Were he here, everything would be alright.

　　Should it rain tomorrow, we would put off the trip.

　　2．虚拟语气用于其他状语从句

　　⑦as if/though引导方式状语从句时，表示现在或将来的虚拟时，从句谓语动词用过去时(be动词一律用were)；表示过去的虚拟时，从句谓语动词用“had＋done”。

　　⑧even if/though引导让步状语从句时，主句和从句都用虚拟语气，动词形式与if引导的非真实条件句的虚拟语气相同。

　　⑨in order that, so that, in case, for fear that引导的目的状语从句中，谓语动词可用(should)do。

　　Keep quiet in case you (should) interrupt him.

　　She is now studying hard for fear that she (should) fail in the exam.

　　3．虚拟语气用于宾语从句

　　⑩wish后的宾语从句中：

　　发生时间 虚拟语气构成

　　发生在主句动作前 had＋done

　　would/could/might/

　　should＋have＋done

　　与主句动作同时发生 过去时(be用were)

　　发生在主句动作后 would/could/might＋do

　　would rather, had rather, would sooner之后的宾语从句中：

　　发生时间 虚拟语气构成

　　过去 had＋done

　　现在 过去时(be用were)

　　将来 过去时(be用were)

　　I'd rather you had seen the film yesterday.

　　I'd rather you were here now.

　　虚拟语气在suggest (建议), arrange, command, demand, desire, insist, order, propose, request, require等后面的宾语从句中，用(should＋) do形式。

　　4．虚拟语气用于主语从句

　　在“It is＋adj./过去分词/n.＋that ...”句型中，that引导的主语从句中谓语动词常用“(should＋) do”形式。

　　常用于此结构的词有：

　　形容词necessary, natural, strange, important, surprising, vital等。

　　过去分词demanded, required, desired, suggested, ordered, decided, requested, recommended等。

　　名词duty, pity, regret, no wonder, shame等。

　　5．虚拟语气用于同位语从句和表语从句中

　　表示“命令、建议、要求、目的和愿望”的名词后面的同位语从句和表语从句中谓语动词用“(should＋) do”形式。

　　用于此结构的常见名词有suggestion, proposal, demand, request, order, advice, desire等。

　　6．虚拟语气的特殊用法

　　if only表示与现在或将来事实相反的愿望时，用过去时或would/could＋do形式；表示与过去事实相反的愿望时，用过去完成时。

　　在“It's (high) time (that) ...”句型中，从句的谓语动词常用虚拟语气表示将来的动作，动词一般用过去时或should＋do形式，should不可以省略。

　　对点训练

　　完成下列小题，并指出考查上述哪个知识点(①～)

　　第一组　单项填空

　　1．(2017·北京卷)If we ________ a table earlier, we wouldn't be standing here in a queue.

　　A. have booked

　　B. booked

　　C. book

　　D. had booked

　　答案　__D__　知识点　__②__

　　解析　句意：如果我们早点预订餐桌的话，我们现在就不会站在这里排队啦。从句为与过去事实相反的虚拟语气，应用过去完成时。

　　2．(2017·安徽卷)I ________ to my cousin's birthday party last night, but I was not available.

　　A. went

　　B. had gone

　　C. would go

　　D. would have gone

　　答案　__D__　知识点　__⑤__

　　解析　由but ...一句知是虚拟，对过去虚拟主句谓语用would have done，故选D项。

　　3．(2017·浙江卷)Eye doctors recommend that a child's first eye exam ________ at the age of six months old.

　　A. was

　　B. be

　　C. were

　　D. is

　　答案　__B__　知识点　____

　　解析　句意：眼科医生建议小孩的第一次眼睛检查应在6个月大时。recommend后接从句，从句谓语动词用should do, should可省去。

　　4．The children must have got lost in the woods; otherwise, they ________ at the lakeside camp as scheduled.

　　A. would have been

　　B. must be

　　C. would be

　　D. should be

　　答案　__A__　知识点　__⑤__

　　解析　句意：这些孩子一定在森林中迷路了，要不然的话，他们早就该按预订的时间在湖边的宿营地了。must have done表示对过去肯定推测，由此可知空处表示与过去事实相反的虚拟语气，应用would/could/should/might have done的形式。

　　5．(2017·淄博二模)— I do want to see the movie.

　　— Okay, if the rain ________ now, we ________ to the theatre.

　　A. stops; go

　　B. could stop; will go

　　C. stopped; would go

　　D. would stop; would to

　　答案　__C__　知识点　__④__

　　解析　由now可知，if从句表示与将来事实相反，谓语动词用一般过去时；主句表示与将来事实相反，谓语动词用would/could/might/should＋do形式。

　　第二组　语法填空

　　6．— What a journey! We've finally arrived!

　　— ________ (have) we not used an out­of­date train schedule, we would not have missed the train.

　　答案　Had　知识点　__⑥__

　　解析　主句表示与过去事实相反，if从句应该用had＋过去分词，省略if后， had提到句首。Had we not used ...是省略if的虚拟条件句，补充完整为“If we had not used ...”。

　　7．Did your boss accept your proposal that we ________ (go) to Wuyuan, the most beautiful countryside in China, to enjoy the attractive scenery?

　　答案　(should)_go　知识点　____

　　解析　proposal后的同位语从句中应使用虚拟语气，即从句中谓语动词用(should＋)do形式。

　　8．It is required that the students ________ (not, use) mobile phones in their school.

　　答案　(should)_not_use　知识点　____

　　解析　句意：学校要求学生在校内不准使用手机。It is required＋that从句，从句谓语应用“should＋do”， should可以省略。

　　9．John wants to see me today. I would rather he ________ (come) tomorrow than today.

　　答案　came　知识点　____

　　解析　句意：约翰想今天来看我。我宁愿他明天来看我而不是今天。在would rather后的宾语从句中，其谓语动词用一般过去式表示对现在或将来的虚拟。

　　10．He opened his lips as if he ________ (say) something to you.

　　答案　would_say　知识点　__⑦__

　　解析　句意：他张开嘴好像要对你说什么。分析句意可知， as if后面的句子需要使用虚拟语气，并且所述内容是对将来情况的虚拟，谓语应用“would＋动词原形”。

　　第三组　单项填空

　　11．There is nothing the matter. I wish you ________ me about it.

　　A. might bother

　　B. should bother

　　C. wouldn't bother

　　D. don't bother

　　答案　__C__　知识点　__⑩__

　　解析　句意：不要紧，请别为我操心。wish后的宾语从句表示与将来事实相反的愿望，从句谓语用“could/would/might＋动词原形”，且结合句意，应用否定形式，故选C项。

　　12．It is already 8 o'clock. It is high time that we ________ out.

　　A. should start

　　B. start

　　C. would start

　　D. will start

　　答案　__A__　知识点　____

　　解析　句意：已经8点钟了。我们该出发了。It is high time that ...句型中，从句的谓语用一般过去时或“should＋动词原形(其中should不能省略)”，故选A项。

　　13．(湖南卷)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__　知识点　__①__

　　解析　从前句可知“我”很忙，后面的句子只是一种假设，是一个含条件状语从句的虚拟语气，是对现在的虚拟， if从句中谓语动词用过去时形式。

　　14．(安徽卷)Grace doesn't want to move to New York because she thinks if she ________ there, she wouldn't be able to see her parents very often.

　　A. lives

　　B. would live

　　C. has lived

　　D. were to live

　　答案　__D__　知识点　__③__

　　解析　句意：格雷丝不想搬到纽约去，因为在她看来，如果她住在那里的话，她就不能经常看到父母了。这是一个含对将来情况提出假设的虚拟语气， if条件状语从句用“were to＋动词原形”，当然也可以用过去式(be的过去式用were)，但A、B、C三项均不符合。

　　15．— Let's play football together tomorrow afternoon.

　　— OK, but how I wish I ________ it as skillfully as you.

　　A. played

　　B. have played

　　C. had played

　　D. will play

　　答案　__A__　知识点　__⑩__

　　解析　wish宾语从句中使用虚拟语气时，表示与现在事实相反，用过去时。

　　16．Tom suggested that I ________ wrong and that I ________ it out in another way.

　　A. should be; should work

　　B. was; worked

　　C. was; work

　　D. be; work

　　答案　__C__　知识点　____

　　解析　suggest作“暗示；启发”解，后接that从句， that从句谓语动词不用虚拟语气，该句主句的谓语动词用的是一般过去时，宾语从句也使用一般过去时，但是从第二个宾语从句的意思看， suggest是“建议”的意思，从句用虚拟语气，由“should＋动词原形”构成，should可省略。