1、专题七情态动词和虚拟语气考点精讲 情态动词考点一情态动词的基本用法1can和could的用法(1)表示“能力”。The man can/could speak two foreign languages那个人能说两门外语。(2)表示推测，一般用于疑问句和否定句。Can the news be true?这个消息可能是真实的吗？It cant be true它不可能是真实的。(3)表示可能性。用于肯定句，常译为“往往会，常常会，有时候可能会”。Accidents can/could happen on rainy days车祸常会发生在雨天。(4)表示请示、允许。口语中常用could代替can。
2、could用以委婉地提出请求等，但回答时必须用can。Can I have a rest?我能休息一下吗？(5)cannottoo/enough表示“无论也不过分”“越越好”。You cant be too careful while driving开车时越小心越好。You cannot remember enough English words你记得的英语单词越多越好。2may和might的用法(1)表示许可。might比may的语气更委婉。You may use my bike你可以用我的自行车。(2)表示推测，意为“可能”。may not表示一种不太确定的语气，意为“可能不”。Some
3、people who dont like to talk much are not necessarily shy; they may just be quiet people言语不多的人未必就是害羞；他们或许就是安静的人。(3)may表示请求时，其否定式常用mustnt表示“禁止”。May I use your car?我可以用一下你的车吗？No，you mustnt不行。(委婉拒绝可用：Sorry，but Im using it now或Youd better not)3must(1)表示义务，意为“必须”(主观意志)。We must do everything step by step我
4、们一切都必须循序渐进地做。特别提示：回答以must开头的问句时，若是否定回答，需要用 neednt 或 dont have to。Must we hand in our exercises today?我们今天必须交练习吗？Yes，you must/No，you neednt/you dont have to是的，必须交。/不，不必。(2)表示推测，意为“一定，必定”，表达十分肯定的语气，只能用于肯定句中。He must be illHe looks so pale他准是病了。他脸色那么苍白。(3)表示“非得，偏要”。Must you make so much noise?你非得弄出这么多噪声
5、吗？4shall和should的用法(1)shall用于第二、三人称的陈述句中，表示命令、许诺、警告、强制、威胁等，此外，颁布法律、法规时也用shall。You shall have a new bike for your birthday你会得到一辆新自行车作为生日礼物。The new law shall come into effect next month新法将于下个月生效。用于第一、三人称的疑问句中，表示说话人征求对方的意见或向对方请示。Shall the man standing outside have a try?让站在外边的那个人试试？(2)should表示义务，常译为“应该”
6、，用于各种人称。Parents should take good care of their babies父母应该照顾好他们的孩子。表示惊讶、意外等，常译为“竟然，居然”。I am surprised that you should speak ill of me我很惊讶，你竟然说我坏话。5will和would的用法(1)表示意愿，用于各种人称的陈述句中。would常指过去的意愿。If you want to read the book，Ill give it to you如果你想读这本书，我可以给你。(2)表示请求，用于疑问句。would语气较委婉。Will you close the wi
7、ndow?请你关上窗户好吗？(3)表示某种倾向或习惯性动作，常译为“总是，习惯于”。would可表示过去反复发生的动作或某种倾向，后面接表示动作的动词，不能接表示状态的词。Every morning he will have a walk along the river每天早晨，他总是沿着小河散步。特别提示：used to表示过去的习惯动作或状态，强调现在已不存在。He would sit in the park which used to be a factory reading for hours他过去常坐在公园里读书，一读几小时，这个公园过去曾经是一个工厂。6need和dare的用法ne
8、ed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。Need I come?我需要来吗？Yes，you must是的，你必须来。You neednt telephone him now你现在不必给他打电话。She dare not go out alone at night她晚上不敢一个人出去。考点二“情态动词have done”的用法1对过去发生的事情或状态进行推测must have done(过去)一定；语气比较肯定；用于肯定句may(might)have done(过去)可能；语气不确定；用于肯定句和否定句can(could)have done(过去
9、)可能，用于否定句和疑问句，表示怀疑或不确定Since nobody gave him any help，he must have done the research on his own既然没有人帮助他，他一定是独自做的研究。Could he have left the work unfinished?他会丢下工作不干了？2表示“与过去事实相反”could have done过去本可以做某事但实际上没做neednt have done过去本不必做某事但实际上做了ought to/should have done过去本应该做某事但实际上没做oughtnt to/shouldnt have do
10、ne过去本不应该做某事但实际上做了would have done过去本来想做某事而没做would not have done过去本不愿意做某事而做了The taxi driver is to blame for the serious accident出租车司机应为这起严重的事故负责。I cant agree moreHe shouldnt have drunk我非常赞同。他本不应该喝酒的。(已经喝了)You neednt have watered the flowers because it would rain soon你本不必浇花的，因为很快会下雨的。(已经浇了)I would have
11、 helped you but I was busy at that time我本来想帮你可是当时很忙。(没有帮)虚拟语气1非真实条件句中虚拟语气的用法说明if条件句谓语主句谓语与现在事实相反动词的过去式(be的过去式通常用 were)would/should/could/might动词原形与过去事实相反had过去分词would/should/could/mighthave过去分词与将来事实相反动词的过去式(be的过去式通常用were)，should do，were to动词原形would/should/could/might动词原形If I were you，I would go with
12、him如果我是你，我就和他一起去。If you had studied harder last term，you could have passed the exam如果上学期你学习更努力的话，你考试就会及格了。If it snowed tomorrow，we would take photos如果明天下雪，我们就照相。特别提示：条件句中有were，had或should时，如果省略if，则需把were，had或should放在主语前，构成倒装结构。If I were in your position，I would do the sameWere I in your position，I wo
13、uld do the same假如我处在你的位置，我也会这样干的。If you had come earlier，you would have caught the busHad you come earlier，you would have caught the bus如果你来得早些，你就会赶上公共汽车了。If it should rain tomorrow，we would not go climbingShould it rain tomorrow，we would not go climbing如果明天下雨的话，我们就不去爬山了。2错综时间虚拟条件句当从句谓语动词与主句谓语动词所发生的
14、时间不一致时，它们的形式要根据各自所发生的时间作出相应的调整。If you had worked hard，you would pass the exam this time(从句指过去，主句指现在)如果你之前努力学习的话，这次你就会通过考试了。3含蓄虚拟语气有时，假设的情况并不用条件从句表达，而是暗含在上下文中，由otherwise，but，or，without，but for 等来表达。But for your help，we couldnt have succeeded(介词短语)要不是你的帮助，我们是不会成功的。Without electricity，life would be qui
15、te different today(介词)如果没有电，今天的生活就会完全不同。I was ill that dayOtherwise，I would have taken part in the sports meeting(副词)我那天病了。否则，我就参加运动会了。He telephoned to inform me of your birthday，or I would have known nothing about it(连词)他打电话通知了我你的生日，否则，我对此一无所知。4某些从句中虚拟语气的用法(1)用于表示建议、愿望、命令等动词后的宾语从句中。常见的动词有：demand，or
16、der，require，insist，suggest，advise，request，urge，command，recommend等。宾语从句中的虚拟语气结构为“should动词原形”，should 可以省略。记忆口诀一主张：insist二命令：order，command三建议：suggest，advise，recommend四要求：request，require，ask，demand外加一个敦促：urgeThe school recommends parents not permit their children to swim in rivers or lakes during summer
17、 holidays学校建议父母们在暑假期间不要让自己的小孩在河里或湖里游泳。特别提示：当suggest作“暗示，表明”，insist作“坚持认为，坚持说”讲时，从句要用陈述语气。The expression on his face suggested that he was very angry他脸上的表情表明他很生气。He insisted (that) he heard someone in the next room他坚持说他听到隔壁屋里有人。(2)wish后跟宾语从句时用虚拟语气。对现在情况的假设：wish主语动词过去式(be动词通常用were)对过去情况的假设：wish主语had过去
18、分词对将来情况的假设：wish主语would/could/might动词原形I wish (that) I were a bird and could fly freely in the sky我希望我是一只小鸟，能在天空自由飞翔。How I wish I had listened to my parents advice!我多么希望我听了父母的建议！I wish I could fly to the moon some day如果有一天我能飞到月球上就好了。(3)在“It is necessary/important/strange/natural/essentialthat从句”中，谓语动
19、词常用“should动词原形”，should 可以省略。It is important that every member (should) know these rules重要的是每个成员都应该知道这些规则。It is necessary that students (should) respect teachers学生应该尊重老师，这是必要的。(4)would rather后跟从句时用虚拟语气，表示愿望，意为“宁愿；但愿”。George is going to talk about the geography of his country，but Id rather he focused
20、more on its culture乔治打算谈论他国家的地理，而我宁愿他更多地关注他国家的文化。(5)在“It is (about/high) timethat 从句”中，谓语动词常用过去式或“should动词原形(其中should不能省略)”。此句型意为“(现在)该”，用来表示建议。It is time that you went to school你该去上学了。It is (high) time that we should start out我们(早)该出发了。(6)if only引导的感叹句中，用虚拟语气表示愿望。Look at the trouble were inIf only
21、we had taken our teachers advice!瞧瞧我们所处的困境，要是我们采纳了老师的建议就好了！(7)as if，as though 引导的表语从句和方式状语从句中常用虚拟语气，与现在事实相反用一般过去时(be动词通常用were)；与过去事实相反用过去完成时；与将来事实相反，用would/could/might动词原形。It seems as though it were spring already看起来好像已经是春天了。(事实上不是)The girl is giving us a vivid description of the moonIt seems as if
22、she had been to the moon many times这个女孩对月球的描述非常逼真，就好像她去过月球很多次似的。He opens his mouth as if he would say something他张开嘴巴，好像要说什么。难点释疑 难点一情态动词的易混点1can与be able to表示“经过努力设法做成某事”时不用can，应用be able to can表示“能力”时，侧重于因有某种知识和技能而能办到某事。【典例】用could或was able to填空The fire spread through the hotel very quickly, but every
23、one _was able to_ get out解析：由句意可知此处应该是所有人经过努力最后出去了，所以应该用was able to。2表示推测的cant与may notcant表示“不可能”，may not表示“可能不，或许不”。很明显，cant比may not语气强。【典例】It _cant_ be the postman at the doorIts only six oclock now解析：cant不可能，在此表示有把握的否定推测，符合句意。3cant，mustnt，neednt cant指“无能力”：mustnt指“不允许，一定不要”；neednt指“不必”：【典例】用cant，
24、musnt或neednt填空(1)There is a meeting insideYou _mustnt_ make any noise解析：句意：里面在开会，你不许制造任何噪音。故应填mustnt。(2)He is too young and _cant_ make a living解析：句意：他太小了不能维持生计。故应填cant。(3)According to todays weather report, it does not rain, so you _neednt_ take the umbrella解析：句意：根据今天的天气预报，今天不下雨，所以你没有必要带雨伞。故应填needn
25、t。难点二对现在/将来/过去的推测 情态动词可以用来对现在、将来和过去进行推测，常用来表示推测的情态动词有can/could，may/might，must，ought to/should等。1情态动词do(1)“mustdo”表示对现在的情况进行有把握的推测，一般用于肯定句，语气最强。There must be something wrong一定出了什么差错。(2)“may/might/can/coulddo”表示对现在或将来发生的事情的推测。 It might snow tomorrow or it might be merely cloudy明天可能下雪，或者可能只是多云。(3)“ough
26、t to/shoulddo”意为“(按道理说)应该”，表示有把握的推测，但语气上留有余地。It should be Mike who has taken away all the materialsHe said he would应该是迈克拿走了所有的材料。他说过他要拿。2情态动词be doing“mustbe doing”表示“准是正在做，一定正在做”。They must be talking about us他们一定正在谈论我们。 3情态动词have done表示对过去发生的事情的推测。(1)must have done意为“一定做了，准是做了，”表示非常有把握的肯定推测；cant/cou
27、ldnt have done意为“不可能做了”，表示非常有把握的否定推测。(2)may/might have done意为“可能/也许做了，”表示对已经发生的事情把握较小的推测。注：“情态动词have done”的用法在前面已进行了详细解释，在此只是简单归纳。解题策略 情态动词和虚拟语气解题“两注意”注意一：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。然后根据句意或句式结构填入恰当的情态动词。注意二：一旦判断所给动词在句中作谓语，就要考虑其时态、语态、语气、主谓一致等，特别是注意虚拟语气中的时态。判断虚拟语气，除了常见的if虚拟条件句，还应注意其他常搭配虚拟语气的标志词，如su
28、ggest，would rather，as if，wish，otherwise，or，but for等。【典例1】I _cant_ thank you enough for what you have done for meYoure welcome解析：cant/can notenough表示“再也不为过”，符合句意。故填cant。【典例2】We took a taxi to the airportOtherwise we _would have been_(be) late解析：根据语境可知，后一句表示与过去事实相反的假设，其谓语应用would have been。易错聚焦 1表达的单调性
29、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Youd better/You might as well/Why not？等。2情态动词搭配错误达标检测 单句语法填空1(2020天津卷改编)Jim says we _can_ stay in his house as long as we leave it clean and tidy解析：考查情态动词。句意：吉姆说我们可以住在他的房子里，只要我们保持它干净整洁。根据后面的“as long as we leave it clean and tidy”可知，J
30、im许可我们待在他的房子里，即：我们“能，可以”待在他的房子里。故填can。2(2020江苏卷改编)If I hadnt been faced with so many barriers, I _would/could/might/should_not be where I am解析：考查虚拟语气。句意：如果我没有面对那么多的障碍，我现在就不会在这里。分析句子成分可知，此处是错综时间虚拟语气，根据空后where I am可知，此处是与现在事实相反的假设，主句谓语动词应使用would/could/might/shoulddo。故填would/could/might/should。3Jack is
31、 a great talker Its high time that he _did/should do_ (do) something instead of just talking解析：考查固定句型It is high time that sb did/should do sth“到某人该做某事的时候了”。故填did/should do。4Excuse me，do you mind if I open the window?Well，if you _must_I can put on more clothes解析：must表示偏要，必须要做的事情。故填must。5Dont handle t
32、he vase as if it_were made_ (make) of steel解析：分析句意可知as if后面的句子要用虚拟语气，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。故填were made。6As the deadline is drawing near, no one _shall_leave with his own work uncompleted解析：shall用于第三人称陈述句中，表示命令、警告，符合句意。故填shall。7My mom suggests that we _(should) eat_ (eat)out for a change thi
33、s weekend解析：suggest表示“建议”时，所跟宾语从句要用虚拟语气，谓语动词用(should) do。故答案为(should) eat。8Grace doesnt want to move to New York because she thinks if she _were to live/should live/lived_ (live)there, she wouldnt be able to see her parents very often 解析：根据wouldnt 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“wer
34、e todo或shoulddo或动词过去式”。故填were to live/should live/lived。9Sorry，I am too busy now If I _had_ (have) time，I would certainly go for an outing with you解析：根据第一句可知设空处是对现在事实的假设，故if从句谓语动词用have的过去式had。10If you leave within 15 minutes，you _can/may_park your car at the roadside temporarily解析：根据语境可知，此处表示“许可”，故用
35、can/may。11(2019天津)The workers were not better organized，otherwise they _would have accomplished_ (accomplish)the task in half the time解析：此处otherwise表达了一种含蓄虚拟；otherwise前的内容所述的是过去的事实，相当于if引导的条件状语从句“If the workers had been better organized”，因此后半部分应用“主语would have done sth”结构。故填would have accomplished。12
36、(2019江苏)What a pity！You missed the sightseeing，or we _would have had_(have)a good time together解析：根据关键词or可知应用虚拟语气，这里表示与过去的事实相反，谓语动词应用would/could/should/mighthave done。故填would have had 。13(2018天津)I cant find my purseI _could/might have left_ (leave) it in the supermarket yesterday，but Im not sure 解析：
37、根据句中时间状语yesterday可知，是对过去发生事情的推测。故用“情态动词have done”，再根据后句but Im not sure可知，此推测为不能肯定的推测。故用could/might have done。14(2018北京)In todays information age，the loss of data _can_cause serious problems for a company 解析：can在此表示客观可能性，意为“可能会，有时候会”。故答案为can。15(2018北京)They might have found a better hotel if they _had
38、 driven_ (drive) a few more kilometers解析：根据主句的谓语形式以及语境(事情已经发生)可知，if条件句应该用过去完成时。表示与过去事实相反的虚拟语气，故从句谓语动词用“had过去分词”。故填had driven。16(2018天津)If we _had caught_ (catch)the flight yesterday，we would be enjoying our holiday on the beach now解析：根据前半句中的时间状语yesterday以及后半部分中的would be enjoying及时间状语now可知，这是一个错综时间虚拟
39、条件句。从句表示与过去的事实相反，故谓语动词用“had过去分词”。故填had caught。17(2018江苏)Its strange that he _should_ have taken the books without the owners permission解析：此处should作情态动词。表示“竟然”，符合语境。故答案为should。18Truly elegant chopsticks might _be made_ (make) of gold and silver with Chinese characters解析：根据语境可知，筷子是“被制造”的。此处为含有情态动词的被动语
40、态might be done。故填be made。19You _must_ be careful with the camera It costs!解析：根据后面的“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。故填must。20(新课标全国样卷)Mum：Are they there? Oh, my goodness I _must_ have put them in there when the phone rang解析：动词原形前常跟情态动词或助动词。根据句意，是对过去发生的动作的最有把握的猜测，故肯定句中用must
41、 have done形式。故填must。单句改错(每小题仅有1处错误)1(2018全国卷)As a kid, I loved to watch cartoons, but no matter how many times I asked to watch them, my parents would not to let me_去掉not后的to_解析：考查情态动词。would后跟动词原形，故把to删除。2Some classmates suggest we can go to places of interest nearby_去掉can或canshould_3He became very
42、angry，but I dared not to tell him about the game_去掉to_4When I got the papers, I realized things could have been better if I listened to the teacher much more attentively_listened前加had_5By the way，should you give me some advice on how to learn maths well?_shouldcould/would_6If you are interested, ple
43、ase let me know as soon as possible In that case, I cant buy the tickets ahead of time_cantcan_7In his opinion，we would not only know“what”， but also understand “why”_wouldshould_8She is a quiet girl at school，but sometimes she must be very naughty_mustcan_9I ought to helped Henry with his work, or
44、he would have finished it now_helped 前加have_10(2020新课标卷I)I like eating fried tomatoes with eggs, and I thought it must to be easy to cook_去掉第一个to_解析：考查情态动词用法。句意：并且我认为它一定很简单。must是情态动词，后接动词原形，must后的to多余，故将must后的to去掉。语法填空Rain or shine, Tom is always the first to arrive at the officeHis home _1must_ be
45、very near the office, or he _2cant_ be always in time for work How I wish that I _3lived_ (live)close to work，so that I _4need_ not get up so early every day Yesterday, for example, I would _5have arrived_ (arrive)in time for work as usual if I hadnt been caught in a traffic jam The boss was so angr
46、y with me that he demanded I _6should_ arrive at work early enough later on，saying that should I be caught late again, he _7would punish_ (punish) me I _8must_ stop everything and go to bed now Anyhow，its time that I _9went/should go_ (go) to sleep，and Id rather I _10arrived_ (arrive) at work on tim
47、e tomorrowIt will be bad to be caught arriving late again 文章大意：作者上班有时会迟到，而他的同事汤姆从来不迟到，因此，作者认为他肯定住得离办公室很近。 解析：1这里用must表示非常有把握的肯定推测，“他的家离办公室肯定很近”。2根据句意可知，这里用cant表示非常有把握的否定推测。3分析句子结构可知，本空在句中作wish后面宾语从句的谓语，此处表示与现在事实相反的假设，从句谓语应用一般过去时。故填lived。4语境表示“这样我就没必要每天起得那么早了”，用need not表示“没必要(做某事)”。故填need。5此处表示与过去事实相
48、反的假设，主句谓语应用“would have done”形式。故填have arrived。6这里是demand后跟宾语从句的句式，此时宾语从句的谓语动词应用“(should)动词原形”。故填should。7这个主从条件句表示对将来的虚拟，主句谓语动词应用“would动词原形”。故填would punish。8这里用情态动词must表示“必须”。故答案为must。9在“Its time that”句型中，从句谓语动词要用过去式或“should动词原形”(should不可省略)。故填went/should go。10在“would rather宾语从句”结构中，对将来的情况进行假设时，宾语从句用
49、虚拟语气，其谓语动词用一般过去时。故填arrived。短文改错I had always gotten along well with my parentsUnlucky，we started to argue about what majors I should choose at university one year agoOur arguments are getting even bad now because the time to complete the application forms and apply to universities are drawing nearI w
50、ant to study computer software programming, so my parents suggest that I must become a doctorAll my parents are doctors，and they see it as carry on a family traditionI had never wanted to be doctor and I hate every minute of itHow can I handle this situation?答案：I had always gotten along well with my
51、 parents，we started to argue about what I should choose at university one year agoOur arguments are getting even now because the time to complete the application forms and apply to universities drawing nearI want to study computer software programming, my parents suggest that I must或 become a doctor my parents are doctors，and they see it as on a family traditionI never wanted to be doctor and I hate every minute of itHow can I handle this situation?
