【简介】感谢网友“雕龙文库”参与投稿，这里小编给大家分享一些，方便大家学习。
第5讲 情态动词和虚拟语气 情态动词
[深化认知]
一、情态动词的基本用法
1．表示能力(can/could/be able to)
表现在的或一般的能力，can与be able to的用法一样，但后者不常用；表将来的能力用will be able to；表示过去一般的能力用could，表示过去有能力并且成功地做了某事用was/were able to，相当于managed to do sth./succeeded in doing sth.。
The man can/could speak two foreign languages.
那个人能说两门外语。
Do you believe that Mozart could play the piano at the age of three?
你相信莫扎特在三岁时就会弹钢琴吗？
The fire spread through the building very quickly but everyone was able to get out.
尽管这场大火很快蔓延到整个大楼，但是每个人都逃出去了。
[名师指津] 如何区分can和be able to
①can在时态上只有现在时和过去时两种，而be able to则有更多的时态。
②be able to强调“通过努力有能力做到”，如果表示“某事已经成功做成”应用was/were able to，而不用could。
③用在其他动词，如might, may, would, want, hope等之后表示能力只能用be able to。
Tom may be able to pass the exam by studying hard from now on.
从现在开始努力学习，汤姆或许能够通过考试。
2．表示推测
(1)can/could表示可能性主要用于否定句和疑问句。
—Can the news be true?
—It can't be true.
——这个消息可能是真实的吗？
——它不可能是真实的。
(2)may/might表推测时主要用于肯定句或否定句中，might的可能性比may更小。
Some people who don't 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。
He was afraid they might not agree with him.
他担心他们可能不同意他的意见。
(3)must表示有把握的推测，意为“想必，准是，一定”等，只用于肯定句中。
He must be ill. He looks so pale.
他准是病了。他的脸色如此苍白。
(4)should表示有一定根据的推测、推论或可能性，意为“想必一定，按说应该，估计”等(肯定的语气没有must表推测时强)。
He should be here on time — he started early enough.
他应该按时到这里的——他出发得够早的。
[名师指津] 如何判断must 表推测时后面的反意疑问句
must表推测时其后的反意疑问句形式等同于去掉must之后的句子的反意疑问句。
如：He must be in class now, ________________？
去掉must后该句为He is in class now，其反意疑问部分为isn't he。故题干空白处也应用isn't he。
He must have already finished his homework, hasn't he?
他肯定已经做完作业了，不是吗？
They must have stayed up last night, didn't they?
昨晚他们肯定熬夜了，不是吗？
3．表示请求、建议、命令、允许、允诺、禁止、义务、责任
(1)请求对方允许时用“May/Might/Can/Could I/we ...？”，给出许可时用may/can。
—Could I use your bike tomorrow morning?
—Yes, of course you can.
——明天早晨我用一下你的自行车，行吗？
——当然可以。
You can/may go with them if you like.
如果你愿意的话，可以和他们一块去。
[名师指津] 回答此类句型时，肯定回答常用“Sure./Of course./Certainly.”或“Yes, of course.”；否定回答常用“No, of course not.”或“No, you can't.”；礼貌回答常用“Sorry, I am afraid I can't.”。
(2)shall 用于第一、三人称疑问句，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？
(3)shall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、强制或威胁。
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。
(4)will表示请求或要求，用于疑问句，常与第二人称连用。
Will you close the window? It's a bit cold.
请把窗户关上好吗？有点冷。
4．表示必要性(must/need/should/ought to)
(1)must表示必要、命令或强制，意为“必须，应该(指说话人的主观意志)”。在回答must引导的问句时，如果是否定的回答，通常不用mustn't，而要用needn't或don't have to。
The children must be back by 4 o'clock.
孩子们必须在4点钟以前回来。
[名师指津] 如何区分must和have to
①must表示主观意志，而have to表示由于客观因素不得不做的事情。
②must没有过去式，除在间接引语中可用于表示过去时间，在直接引语中表示过去时间应该用had to代替。
③在否定结构中don't have to表示“不必”，mustn't表示“禁止”。
I told her that she must give up smoking.
我告诉她必须戒烟。
We had to get everything ready that night.
我们那晚得把一切准备就绪。
You don't have to tell him about it.
你不必把此事告诉他。
You mustn't leave the gate open.
你不要让大门敞开着。
(2)need用作情态动词时，没有词形的变化，后面跟不带to的不定式(即动词原形)，通常用于否定句和疑问句中。
You needn't telephone him now.
你现在不必给他打电话。
(3)should/ought to表示义务、责任或劝告、建议、命令等，意为“应该”，用于各种人称。
You should/ought to
be polite to your teachers.
你应该对老师有礼貌。
5．表示意愿、决心
will/would可与各种人称连用，表示主语的意志或决心。will表示意愿时其否定形式won't通常用于有生命体，但有时也用于无生命体，这时把无生命体拟人化了。
You can stay here as long as you can, if you will.
如果你愿意，你在这里能待多长时间就待多长时间。
—Why didn't you come to Simon's party last night?
—I wanted to, but my mom simply would not let me out so late at night.
——你昨晚为什么没有参加西蒙的聚会？
——我想去，但是妈妈不愿意让我自己在这么晚的时间出去。
二、情态动词的特殊用法
1．can的特殊用法
(1)表示可能性(理论上或逻辑判断上)。
On such a rainy day, accidents can happen.
在这样的下雨天，有时会发生事故。
(2)表示惊异、怀疑、不相信等态度，主要用于否定句、疑问句或感叹句中。
How can you be so careless while driving?
你开车时怎么这么粗心呢？
(3)cannot ... too/enough表示“无论……也不过分，越……越好”。
You cannot remember enough English words.
你记的英语单词越多越好。
2．may的特殊用法
(1)may as
well＋动词原形，意为“最好，不妨，干脆”。
You may as well do it at once.
你最好马上就做这件事。
(2)表示祝愿，常用于“May＋主语＋动词原形”结构。
May you have a good trip.
祝你们旅途愉快。
3．must的特殊用法
must表示“偏要，硬要(做某事)”，指令人不快的事情。
Must you make so much noise?
你非得弄出这么多噪音吗？
4．shall的特殊用法
shall用于第三人称的陈述句中，在条约、规定、法令等文件中表示义务或规定。
It has been announced that candidates shall remain in their seats until all the papers have been collected.
已宣布，在所有试卷收上来之前，应试者必须留在自己的座位上。(规定)
5．should的特殊用法
(1)should多用于疑问句中，表示惊讶、难以相信或不应该的事，常与why或how连用，意为“竟会”。
Why should you be so late today?
今天你怎么会这么晚？
(2)(表示可能)假如，万一
Should anyone call (＝If anyone calls), please tell him I'm busy.
如果有人打电话来，请告诉他我正忙着。
6．will/would的特殊用法
will/would表示某种倾向或习惯性动作，意为“经常，惯于，总是”。
Every morning, he will have a walk along the river.
每天早晨，他总是沿着小河散步。(习惯性动作)
三、“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 用于否定句和疑问句，表示怀疑或不确定
—Has Peter started out？He said he would go hiking with us.
—He must have started. He is a man of his word.
——Peter 已经出发了吗？他说他会与我们一起去远足。
——他肯定已出发了。他是一个信守诺言的人。
2．表示“与过去事实相反”的虚拟语气
could have done 过去本来可以做某事但实际上没做
needn't 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
oughtn't to/
shouldn't
have done 过去不应该做某事但实际上做了
might have done 过去可能发生但实际上没发生
You needn't have taken a taxi here, for it was near my home.
你本来不必打车来这里的，因为这里离我家很近。
[典题在线]
Ⅰ.用适当的情态动词填空
1．(2024·北京高考单选)—Can't you stay a little longer?
—It's getting late. I really must go now. My daughter is home alone.
2．(2024·陕西高考单选)You may/might feel all the training a waste of time, but I'm a hundred percent sure later you'll be grateful you did it.
3．(2024·重庆高考单选)You must be Carol. You haven't changed a bit after all these years.
4．(2024·四川高考单选)You must be careful with the camera. It costs!
5．(2024·福建高考单选)—Sorry, Mum! I failed the job interview again.
—Oh, it's too bad. You should_have_made (make) full preparations.
6．(2024·全国样卷语法填空)Are they there? Oh, my goodness. I must have put them there when the phone rang.
7．(2024·大纲卷单选)Although you can find bargains in London, it's not generally a cheap place to shop.
8．(2024·江苏高考单选)It was sad to me that they, so poor themselves, should bring me food.
9．(2024·北京高考单选)Can/May I have a word with you? It won't take long.
10．(2024·辽宁高考单选)Harry is feeling uncomfortable. He must_have_drunk (drink) too much at the party last night.
11．(2024·重庆高考单选)—Must you interrupt now? Can't you see I'm on the phone?
—Sorry Sir, but it's urgent.
Ⅱ.单句改错
1．(2024·全国卷Ⅰ短文改错)We must found ways to protect
the
environment. If we fail to do so, we'll live to regret it.found→find
2．(2024·全国卷Ⅱ短文改错)We can lie on the grass for a rest, or sat by the lake listening
to
music. sat→sit
虚拟语气
[深化认知]
一、if条件句中的虚拟语气
if条件
从句 从句的谓语形式 主句的谓语形式
表示与
现在事
实相反 动词过去式(be的过去式用were) should/would/could/might＋动词原形
表示与
过去事
实相反 had＋过去分词 should/would/could/might＋have＋过去分词
表示与
将来事
实相反 should＋动词原形 should/would/could/
might＋动词原形
动词过去式
(be的过去式用were)
were to＋动词原形
If you didn't smoke so much, you might get rid of cough sooner.
如果你不抽那么多烟，你可能很快就不咳嗽了。
We would have called a taxi yesterday if Harold hadn't offered us a ride home.
如果昨天哈罗德没送我们回家，我们会打出租车回家的。
Grace doesn't want to move to New York because she thinks if she were to live there, she wouldn't be able to see her parents very often.
格雷丝不想搬到纽约，因为她认为，如果她住到那里去，她就不能经常看到父母了。
二、错综时间条件句的虚拟语气
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，被称为“错综时间条件句”，动词的形式要根据它所表示的时间做出相应的调整。
If we had booked a table earlier, we wouldn't be standing here in a queue.
如果我们早一点订一张桌子，现在就不会站在这里排队了。
If you hadn't left home without a word, your parents wouldn't be so worried now.
要是你说句话再离开家，你父母现在就不会那么担心了。
三、省略if的倒装句
在虚拟条件状语从句中可省略if，把were, had, should提到句首，变为倒装句式。
Were she to live abroad, she wouldn't be able to see her best friends very often.
如果她住到国外，她就不能经常看到她最好的朋友了。
Had he caught the morning train, he would not have been late for the meeting.
如果他赶上了早班火车，他就不会开会迟到了。
四、含蓄条件句中的虚拟语气
有时假设的情况并不以条件从句表示，而是由otherwise, but, or, without, but for等来引导或者通过上下文引出。
