第七节 情态动词和虚拟语气
考点一
情态动词的基本用法
1．can
(1)表示能力。需注意的是，could表示过去一般的能力，而was/were able to表示有能力而且成功地做成了某事。
However great the difficulties may be，we can overcome them.
哪怕是再大的困难我们也能克服。
The fire spread through the building very quickly，but everyone was able to get out.尽管这场大火迅速蔓延了整个大楼，但是每个人都逃了出去。
(2)表示理论上的可能性，意为“有时候可能会”。
Everything can happen；everything is possible and probable.
任何事情都有可能发生，没有什么是不可能的。
(3)表示请求和允许。在问句中，could比can语气要委婉；但答语中要用can表示直截了当。
—Could I use your cell phone?
——我可以用你的手机吗？
—Of course you can.——当然可以。
(4)表示推测，常用于疑问句和否定句。
What can they be doing there?
他们可能正在那里干什么？
He can't be in the office，for the light has been turned off.他不可能在办公室，因为灯已关了。
[名师点津] can't/can never be too.../can't/can never be...enough表示“再……也不为过”。
You can never be too careful/careful enough while driving a car.开车时如何小心都不为过。
2．may
(1)表示请求、允许，此时might比may的语气更委婉。
—May/Might I play basketball this afternoon?
——今天下午我可以打篮球吗？
—No，you may not.——不，不行。
(2)表示推测意为“可能、或许”。
We may go to the cinema tonight，but we are not sure yet.我们今晚或许去看电影，但还未确定。
(3)用于祈使句中表示祝愿。
May you be happy every day and succeed in your work！祝你每天都过得开心且工作顺利！
[名师点津] “may as well＋动词原形”意为“最好，倒不如”。
There is nothing to do，so I may as well go to bed.
没什么事可做，我还是上床睡觉好了。
3．must
(1)表示“必须，应该”，must一般指主观，而have to指客观，表示“不得不”。
We must do everything step by step.
我们一切都必须循序渐进地做。
I have to go now for I've a meeting 15 minutes later.
我必须走了，因为15分钟后有个会。
(2)表示推测，意为“一定会”，此时不能用于否定句。
He must be ill.He looks so pale.
他一定病了，他的脸色苍白。
(3)mustn't表禁止，而have to的否定式意为“不必”。
Smoking mustn't be allowed in the office.
办公室里不许吸烟。
—Must we hand in our exercise today?
——我们今天必须交作业吗？
—No，you don't have to.——不，不必今天交。
[名师点津] must表示偏执、固执，意为“偏要，硬要”。
If you must smoke，please go out.
如果你硬要吸烟，那就出去吧。
4．shall
(1)用于第一、三人称的疑问句中，用于征求对方的意见。
Shall I buy some picture books for the children?
要我给孩子们买些图画书吗？
(2)用于第二、三人称的陈述句，表示说话人给对方的命令、警告、允诺或威胁；此外，当颁布法律、规定时也用shall。
You shall do as your teacher says.
你得按你老师说的那样做。
5．should
(1)表示劝告和建议，意为“应该”。此时ought to比should语气要强。
You should/ought to put more effort into your work.
你应该更加努力地工作。
(2)表示预测可能性，意为“按道理应该会”。
He left Paris in the morning.So he should arrive here by supper time.
他早上离开巴黎，因此他晚饭前应该能到这里。
[名师点津] should表示惊讶、意外等情绪，意为“竟然”。
It is strange that such things should happen in our school.
真奇怪，这样的事情竟然在我们学校发生了。
6．will/would
(1)表示意愿，可用于各种人称。
We will never give up working，whatever happens.
无论发生什么事，我们都不会放弃工作。
(2)表示“请求，建议”，此时would比will更委婉。
Would you come into the bar and have a drink with me? 你愿意进酒吧和我喝一杯吗 ?
[名师点津] will/would表示习惯，意为“总是，习惯于”。与used to相比，would表示过去重复、习惯性动作；而used to则强调过去与现在的对比。
She'll listen to music，alone in her room，for hours.
她总是独自一个在房间里听音乐，一听就是几个小时。
Last year our English teacher would tell us stories in English after class.去年我们的英语老师常常课后给我们用英语讲故事。
He used to spend all his money on food and drink，now he lives a simple life.
他过去把钱都花在吃喝上，现在可节省了。
7．need/dare
need和dare既可作实意动词又可作情态动词，用作情态动词时，主要用于疑问句和否定句。
He need not go if he doesn't want to.
如果他不想去，他就不必去。
How dare you say such a thing?
你竟敢说出这种话呀？
考点二
“情态动词＋have done”的用法
情态动词＋have done 用法
must have done 一定做过某事，其否定形式为can't/couldn't have done
can/could have done 1.本来能够做但却未做
2.可能做过某事
can't/couldn't have done 不可能做过某事
may/might have done 或许/可能做过某事
should/ought to have done 本该做但却未做，其否定形式表示本不该做但却做了
needn't have done 做了本没有必要做的事情
—Wang Yaping was the second woman to be sent into space in China.
——王亚平成为第二名被送入太空的中国女性。
—She must have gone through tough training.
——她肯定受过艰苦的训练。
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。
考点三
虚拟语气在非真实条件句中的用法
if条件从句 从句的谓语形式 主句的谓语形式
表示现在情况 动词过去式(be的过去式用were) should/would/could/might＋动词原形
表示过去情况 had＋过去分词 should/would/could/might＋have＋过去分词
表示未来情况 should＋动词原形 should/would/ could/might＋动词原形
动词过去式
were to＋动词原形
If I were you，I would take action right away.
如果我是你，我会立即采取行动。
If you had got up earlier，you would have caught the train.如果你早点起床，你就会赶上火车了。
If you should fail，what would you do?
万一你失败了，你准备怎么办？
考点四
虚拟条件的三种特殊形式
if省略句 如果虚拟条件句中含有were/had/should，可把if省略，把were/had/should提到主语之前形成倒装，若为否定形式，not不可提前。
混合条件句 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各自表示的时间加以调整。
含蓄条件句 有时假设的情况不用条件从句表达，而是用but for，without等介词(短语)或上下文来表示条件。用连词otherwise，or等暗示后文与前面的情况相反，从而引出后文的虚拟语气。虚拟条件通过but暗示出来，模式为“虚拟情况＋but＋真实情况”。
Were it Sunday tomorrow，we should go to the Great Wall.
要是明天是星期日，我们就能去长城了。
If you had prepared in advance，you wouldn't be in such an awkward position now.
如果你事先做好准备，现在就不至于那么被动。
But for you，we couldn't have carried out the plan.
要不是你的话，我们(当时)无法实行那项计划。
考点五
虚拟语气的其他情况
1．wish后面宾语从句的虚拟语气
与现在事实相反 从句用一般过去时
与过去事实相反 从句用过去完成时
与将来事实相反 从句用would＋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。
2．表示主张、命令、建议、要求等词后的宾语从句中常用“(should＋)动词原形”结构
[名师点津] 当insist表示“坚持认为；坚持说”；suggest表示“暗示，表明”时后面的宾语从句不用虚拟语气。
The young man insisted that he did nothing wrong and should be set free at once.
这个年轻人坚持认为他没有做错，坚决要求马上被释放。
The girl's pale face suggested that she was ill and I suggested that she go to see the doctor at once.这个女孩苍白的脸色表明她病了，我建议她马上去看医生。
Teachers recommend parents not allow their children under 12 to ride bicycles to school for safety.
老师们建议父母，为了安全不要让他们12岁以下的孩子骑车上学。
3．用于主语从句、表语从句和同位语从句中
(1)表示要求、命令、建议、意图、决定、推荐等意义的动词，构成it is＋动词的过去分词＋that ...时，that从句中的谓语动词用(should＋)动词原形。
It is advised that the meeting (should) be put off until next week.
有人建议会议推迟到下周举行。
(2)表示要求、命令、建议、意图、决定、推荐等意义的名词，如suggestion，proposal，advice，order，request等后面的表语从句和同位语从句中，谓语动词用(should＋)动词原形。
My request is that you (should) make an apology to your teacher.我的要求是你向你的老师道歉。
I made a suggestion to him that he should join the club activities.我建议他应该参加该俱乐部活动。
4．用于定语从句中
It's (high/about) time (that) ...句型中，从句的谓语动词用一般过去时或should＋动词原形(其中should不可省略)，句意为“确实到了……的时候了”。
It is high time that we took some measures to solve the problem.
确实到了我们采取措施解决问题的时候了。
5．用于as if引导的从句中
表示与现在事实相反用一般过去时；表示与过去事实相反用过去完成时。
People treat him as if he were a dangerous person.
人们把他看作是一个危险人物。
He talks as if he had been to many countries.
他说起话来好像去过好多国家似的。
6．用于if only引导的感叹句中，其用法相当于wish后的宾语从句
He didn't pass the driving test，again.If only he had been more careful.他又没通过驾驶考试。要是他再仔细些就好了。
[本节小结]
情态动词和虚拟语气均是近几年高考重点考查的项目。对情态动词，侧重其表示推测与可能性的考查，其中考查“情态动词＋have done”结构表示对过去发生的事情的推测尤其突出。对虚拟语气的考查常与情态动词表示推测的语气混合在一起进行。因此考生在备考中要了解常见情态动词的语法特征、语义特征以及相互间的区别；准确把握情态动词表推测、判断的用法；虚拟语气在名词性从句中的应用等方面。未来高考考查该类考点的有效信息会越来越隐蔽，情景会越来越生动，考查角度也会越来越综合化，因此考生要给予足够的重视。
针对训练
.用适当的情态动词填空
1．(2017·北京高考)________I have a word with you? It won't take long.
【答案】 Can
2．(2017·大纲全国卷)Although you ________ find bargains in London，it's not generally a cheap place to shop.
【答案】 can
3．(2017·湖南高考)—I've prepared all kinds of food for the picnic.
—Do you mean we ________ bring anything with us?
【答案】 needn't
4．(2017·江苏高考)It was sad to me that they，so poor themselves，________ bring me food.
【答案】 should
5．(2017·江西高考)Life is unpredictable；even the poorest ________ become the richest.
【答案】 might
6．(2017·四川高考)I still remember my happy childhood when my mother ________ take me to Disneyland at weekends.
【答案】 would
7．(2017·重庆高考)I've ordered some pizza，so we
________ worry about cooking when we get home tired.
【答案】 needn't
8．(2017·新课标全国卷)Since nobody gave him any help，he ________ have done the research on his own.
【答案】 must
9．(2017·四川高考)—Why are your eyes so red? You ________ have slept well last night.
—Yeah，I stayed up late writing a report.
【答案】 can't
10．(2017·陕西高考)My mom suggests that we ________ eat out for a change this weekend.
【答案】 should
.用所给动词的适当形式填空
1．(2017·福建高考)________(be)there no modern telecommunications，we would have to wait for weeks to get news from around the world.
【答案】 Were
2．(2017·湖南高考) If Mr Dewey ________ (be)present，he would have offered any possible assistance to the people there.
【答案】 had been
3．(2017·陕西高考)We would rather our daughter ________ (stay)at home with us，but it is her choice，and she is not a child any longer.
【答案】 stayed
4．(2017·天津高考)If
he ________(catch) the morning train，he would not have been late for the meeting.
【答案】 had caught
5．(2017·浙江高考)They were abroad during the months when we were carrying out the investigation，or they ________ (come)to our help.
【答案】 would have come
6．(2017·重庆高考)It was John who broke the window.Why are you talking to me as if I ________ (do)it?
【答案】 had done
7．(2017·北京高考)We ________(be)back in the hotel now if you didn't lose the map.
【答案】 would be
8．—Where are the children? The dinner's going to be completely ruined.
—I wish they ________ (not be) always late.
【答案】 weren't
9．He insisted he ________ (send) to the city.
【答案】 (should) be sent
10．His expression suggested that he ________ (pass) the test.
【答案】 had passed
综合演练
.语篇填空
用适当的情态动词完成下列短文
Miss Fang 1.________ (not) read for very long with getting a headache.Her mother told her that she 2.________ go to the Health Service and see a doctor.“You 3.________ see a doctor as soon as possible，” she said.“You 4.________ need glasses.”
When Miss Fang had free time，she went to the Health Service.The appointment clerk said that the doctor 5.________ see her at 3：30.
Miss Fang replied that she 6.________ not be able to be there at 3：30 because she had a class then.“The doctor 7.________
take you at about ten to four，” the appointment clerk suggested.
“8.________ I put you down for ten to four，or 9.________ you rather come tomorrow？”
Miss Fang thought she 10.________ (not) waste any more time.The teacher 11.________ be unhappy if she asked for permission to leave the class a little early，as he was always so kind to everyone.And she replied，“I think I 12.________ make it at ten to four.”
Miss Fang went to the class.She asked her teacher，“13.________ I leave at 3：35 today? I 14.________ have an eye examination.” As expected，the teacher said，“Yes，of course you 15.________.”
【答案】 1.couldn't 2.should 3.should 4.might
5．could 6.would 7.might 8.Shall 9.would
10．shouldn't 11.shouldn't 12.can 13.May/Can
14．must 15.can
.语法填空
用虚拟语气完成下列短文(每空不多于3个单词)
I am a middle school student.I have many dreams.If there 1.________(be) not so much homework，I would have more time to do what I like to do.How I wish I 2.________(listen)to my favorite music for an hour a day and 3.________(play)table tennis for an hour in the morning！It's my desire that we 4.________(hold)evening parties or 5.________(organize)some interesting activities at weekends.I suggest that there 6.________ (be) not so many tests.You can imagine what life 7.________ (be) if I 8.________(realize) my dream.But I must face the exams.Without good marks，I 9.________(not enter) my ideal university.Anyway，it's high time that I 10.________(encourage)myself and worked hard from now on.
【答案】 1.were 2.listened 3.played 4.(should)hold 5．(should)organize 6.(should)be 7.would be 8.realized/should realize 9.wouldn't enter 10.encouraged