情态动词 情态动词的基本用法

(共20张PPT)
(六)情态动词
一、情态动词的基本用法
1.can
(1)(表示能力)能……；会……
She can drive，but she can’t ride a bicycle.
【注】　could表示“原来具备某种能力，现在没有这种能力
了”，但was/were able to则表示过去成功地做成了某事。
I could swim all the way across the lake，but I can’t now.
我原来 能游过这个湖，但现在不能了。
The fire spread through the hotel very quickly but everyone was
able to get out.
大火很快蔓延了整个旅馆，但全体人员都脱离了危险。
(2)(表示可能、许可)能够……；可以……
“Can I use your telephone？”“Yes，of course you can.”
You can’t park your car in this street.
【注】　can可作“有时候会……”解，意思是平时或大部分时间不
是这样子，只是偶尔发生的事情。如：
Jogging can be harmful to the health.
慢跑有时候会对身体健康有害。
(3)(表温和的命令)请做……，得……
I’ll do the cooking，and you can do the washing.
我来做饭，请你去洗衣服。
(4)(用于疑问句中，表请求、提议)能不能……；要不要……
Can you give me a lift to the station
Can’t you lend me ten dollars？请你借给我10美元吧？
(5)(用于疑问句中，表惊讶、怀疑等)“(到底)可能有这样的事吗？”
Can it be that it was I，not he，who was mistaken？
难道错的会是我，而不是他吗？
(6)构成下列特殊句式：
①can not/can never...too...或cannot...enough
“无论怎么……也不过分；越……越好；非常……”。
One cannot be too careful. 越认真越好。
I cannot thank you enough.我对你感激不尽。
②cannot help doing.../cannot help but do.../cannnot but do...
“禁不住；不由得；不得不”。
I cannot help admiring the picture whenever I look at it.
When a close friend dies，you cannot but feel sad.
2.may
(1)(表准许、请求)可以……
You may go home now，Susan.苏珊，你现在可以回家了。
May I have a word with you，please？我可以跟你说句话吗？
(2)(表愿望、祝福)但愿；祝……。此时，句子要用倒装语序。
May you succeed！祝你成功！
(3)(用于目的状语从句中)为了；为了能够
He works hard so that he may get good grades.
(4)(用于让步状语从句中)即使；无论
Whatever he may say，I don’t believe him.
(5)构成句型：may/might as well do sth.
“还是做某事的好；不妨去做某事”
Since we’ve got nothing better to do，we might as well go for a
walk.既然我们没什么更好的事情可做，我们不妨去散散步。
3.must
(1)(表义务、必要性、命令)必须，得，要
“Must I wash the dishes at once？”“No，you needn’t.”
“我得立刻洗这些盘子吗？”“不，不必。”
Animals must eat to live.为了活下去，动物必须吃东西。
【注】　mustn’t表“禁止、不准”。
You mustn’t play with the knife；you may hurt yourself.
你不可玩刀子，你会把自己割伤的。
(2)(表必然性)必定
Everyone must die.每个人都必定会死。
(3)(表固执、不满等)偏偏；硬要；偏要
If you must know，I’m going to help him look for an apartment.
如果你偏要知道，那我告诉你，我要去帮助他找一套公寓。
4.shall
(1)用于疑问句中，与第一、三人称连用，表示征求对方的意见
Shall she go to the concert with us this evening
Shall we go out for a walk
【注】　may用于征求对方的许可，shall用于征求对方的意见或
指示。
May I have a look？我能看一下吗？
Shall I have a look？要我看一下吗？
(2)用于第二、三人称，表示说话人的命令、警告、强制、允诺、
威胁或决心等
Don’t worry.You shall get the answer this very afternoon.
不要焦急，今天下午你就会得到答复。(允诺)
He shall be sorry one day.I tell you.
我告诉你，他早晚有一天会后悔的。(警告)
(3)(用于法律、规则等条文中)应……，须……，得……
The fine shall be given in cash.罚款应以现金缴纳。
5.should
(1)(表义务、责任)应该
We should attend the meeting.我们应该参加这次会议。
(2)(表预期)应该会，想必会，一定会……吧
The concert should be great fun.音乐会一定会很有意思。
(3)(表惊讶、遗憾)竟然；居然
I’m glad that your story should have won the first prize.
我很高兴你的小说居然赢得头奖。
(4)(与疑问词连用，表示意外、纳闷、惊讶等)究竟是；到底
Who should come in but my old friend Betty！
我当是谁进来了呢，原来是我的老朋友贝蒂呀！
(5)(用于条件状语从句中)一旦；万一
If she should know the truth，she would be greatly depressed.
万一她知道了实情，她将会非常失望。
Should you change your mind，let us know.
你一旦改变主意，就通知我们。
(6)(用于表示命令、建议、请求的动词后面的that从句中，且
should可省略)应该；必须
She demanded that they (should) leave at once.
她要求他们立即离开。
(7)(用于以lest，for fear that，in case引导的状语从句中)以免；唯 恐
She gave me a list just in case I should forget what to buy.
她给了我一张清单，以免我忘记买些什么。
6.would
(1)(表过去的习惯性动作)(从前)常常；经常
We would stay up all night talking about our future.
那时候，我们常常彻夜谈论我们的将来。
(2)(表示说话者的厌烦、焦躁)老是；偏要
That’s exactly like Susie.She would come to me just when I was busy.
苏西就是那个样子，她老是在我忙碌的时候来找我。
(3)(用于否定句中，主语一般是事物，表示某事物暂时的特
性)就是(不能)
That window wouldn’t open.那扇窗户打不开。
(4)表示请求或个人的想法、看法，使语气婉转
Would you mind if I opened the window？
我打开窗户你不介意吧？
二、情态动词表推测
情态动词must，can/could，may/might可以用来对事情进行推
测。must表推测时只能用于肯定句，是对现在或过去的事情进行的
推测，不能表对将来事情的推测，语气非常肯定，译为“一定……”。
can/could表推测时一般用于否定句或疑问句，也是对现在或过去的
事情进行推测，但could偶尔可用于肯定推测。may/might表推测时
一般用于肯定句或否定句，可对现在、过去或将来的事情进行推测，
语气不很肯定，译为“可能……”。
此时，一般有两种结构：“情态动词＋be”和“情态动词＋have
done”。
1.“情态动词＋be”结构通常用来对现在或将来的状况进行推测。
The light is still on.He must be working in the office now.
灯还亮着，他现在一定还在办公室工作着。
Michael can’t be a policeman，for he’s much too short.
麦克不可能是警察，因为他太矮了。
He may be in the classroom.I’ll go and make sure.
他或许在教室里，我去弄弄清楚。
2.“情态动词＋have done”结构用于对过去事情的推测。
I didn’t hear the phone.I must have been asleep.
我当时没有听到电话响，我一定是睡着了。
Tom hasn’t come back yet.He may have missed the bus again.
汤姆还没有回来，他可能又没赶上班车。
Jack can’t have arrived yet；otherwise he would have
telephoned me.杰克不可能来到，否则，他会给我来电话的。
【注】　might have done和could have done除了表对过去事情
的推测外，还可表示一种责备语气，意为“(过去)本来可以(能
够)做某事，但实际上没有做到”，此时不能用may或can。
He might have given you more help，even though he was very
busy.即使再忙，他也可能再多给你一些帮助的。
三、情态动词表责备语气
情态动词should，ought to，could，might，need等常用来表
示说话人对过去事情的不满或遗憾，带有较强烈的责备语气。
1.should (ought to) have done “本应该……”，表示过去应该做而
(实际)没有做的事情，含有责备或遗憾的语气，其否定形式为
“should not/ought not to have done”。
I told Sally how to get there，but perhaps I should have written
it out for her.当时我告诉了莎丽如何去那儿，但或许我还是该给
她写出来为好。
【注】should have done还可以表示惊讶、赞叹等情绪。
It’s wonderful that you should have achieved so much in these
years.太神奇了，这几年你竟然取得了这么大的成就。
2.could/might have done “本来能够(会)……”，表示过去本来可以
(能够)做某事，但实际上没有做到。
—I didn’t go to class last night because my car broke down.
—You could have borrowed mine.I wasn’t using it.
“我昨晚没去上课，我的车坏了。”
“那你该借我的呀，我那时没用它。”
3.needn’t have done“本来不需要……”，表示过去本来没有必要做
某事，但事实上却做了。
There was plenty of time.She needn’t have hurried.
当时时间很充足，她本没有必要那么匆忙的。
过关落实
1.—How’s your tour around the North Lake Is it beautiful
—It ________ be，but it is now heavily polluted. 　　
A.will B.would C.should D.must
解析：should译为“应该”，含有批评的语气。
答案：C
2.—What does the sign over there read
—“No person ________ smoke or carry a lighted cigarette，cigar
or pipe in this area.”
A.will B.may C.shall D.must
解析：shall表示按法律，规则等条文规定“必须……”。
答案：C
3.—She looks very happy.She ________ have passed the exam.
—I guess so.It’s not difficult after all.
A.should B.could C.must D.might
解析：must have done表示对过去事情的肯定推测，译为“肯定
发生过某事”。
答案：C
4.—Where is my dictionary I remember I put it here yesterday.
—You ________ it in the wrong place.
A.must put B.should have put
C.might put D.might have put
解析：might have done表示对过去事情的不太肯定的推测，译
为“或许发生过某事”。
答案：D
5.The teacher ________ have thought Johnson was worth it or she
wouldn’t have wasted time on him，I suppose.
A.should B.can C.would D.must
解析：must have done表示对过去事情的肯定推测。
答案：D
6.My MP4 player isn’t in my bag.Where ________ I have put it
A.can B.must C.should D.would
解析：在否定和疑问句中只能用can表推测。
答案：A
7.—My cat’s really fat.
—You ________ have given her so much food.
A.wouldn’t B.couldn’t C.shouldn’t D.mustn’t
解析：shouldn’t have done表示本不应该做某事但实际上却做
了，含有责备的语气。
答案：C
8.The biggest problem for most plants，which ________ just get up
and run away when threatened，is that animals like to eat them.
A.shan’t B.can’t C.needn’t D.mustn’t
解析：根据上下文的意思应用can’t表示能力。
答案：B
9.There’s no light on—they ________ be at home.
A.can’t B.mustn’t C.needn’t D.shouldn’t
解析：对现在事实的否定猜测，用can’t。
答案：A
10.If it were not for the fact that she ________ sing，I would invite
her to the party.
A.couldn’t B.shouldn’t
C.can’t D.might not
解析：此处can’t表示不具有某种能力(不会)。
答案：C
11.Don’t interrupt me，John.________ you force me to tell you the
truth at the moment
A.Might B.Must C.Should D.Would
解析：Must you...？你一定要/非要……吗？
答案：B
12.The public transportation is very convenient in that big city，so
there ________ be any difficulty in traveling around.
A.mustn’t B.wouldn’t
C.shouldn’t D.needn’t
解析：shouldn’t句中意为“应该不会”。
答案：C
13.—Has the manager gone on business
—No.He ________ have but something prevented him at the last
minute.
A.could B.may C.can D.mustn’t
解析：句意为“他本来应已出差，但有事情在最后一刻发生阻
碍了他”。
答案：A
14.Our holidays were ruined by the weather；________ have
stayed at home!
A.it may be as well B.it was just as well we
C.we might just as well D.we might do as well as we
解析：might (just) as well意为“只好”。
答案：C
15.—How exciting! I drove my new car at a speed of 120 km/h on
Sunday morning.
—Were you crazy You ________ yourself!
A.must have killed B.should have killed
C.might have killed D.need have killed
解析：考查情态动词。“might have ＋过去分词”是对过去情
况的 可能性推测，此处含有“责备，批评”的意味。此题易误
选B。
答案：C