（人教版）高中英语必修3：Unit 2 Healthy eating情态动词及语法讲解（Ⅱ）

情态动词（II）
概念引入
Such things ought not to be allowed. 这类事不该容许。
He said I ought to write an article about it. 他说我应当写一篇文章谈这事。
I ought to be fit for work next month. 下个月我想必可以工作了。
I don’t think you ought to have done that. 我想你不应该这样做的。
上一单元我们学习了英语中的大部分的情态动词，本单元我们会重点学习ought to的用法，并小结一下表示推测的情态动词，及三个用法与情态动词的相同的短语had better，used to和would rather。
语法讲解
ought to的用法讲解
1. 与众不同的ought to
ought to是一个比较奇怪的情态动词，因为其他所有情态动词都后接动词原形，而ought to虽然也是后接动词原形，但却无意中构成了ought to do sth结构，其中的to do sth.便是一个典型的带to不定式，并且ought to do sth在用法上也是基本上将ought与to do sth
分开使用——如构成疑问句，只需将ought提前，而不是将ought to提前；构成否定式时，是在ought后面加上not，而不是在ought to的后面加not。如：
Ought I to tell her the truth? 我应该把真实的情形告诉她吗？
We ought to be careful，oughtn’t we? 我们应该小心，对吧?
Oughtn’t he to see a doctor? 他是不是该去看医生?
You oughtn’t to stay out so late. 你不应当在外面待到这样晚。
在美国英语中，ought to用于否定句和疑问句时可将其中的to省略。如：
Ought we (to) have done it? 我们本该做此事吗?
但是，肯定句中的to通常是不会省略。另外，在简略答语中，有时也可以省去to。如：
—Ought he to go with us? 他应该同我们一起去吗?
—Yes, he ought (to). 对，应该一起去。
2. 具体用法
1. (表示义务、责任等) 应当，应该（与should同义，语气稍重）
You ought to work harder than that. 你应该比那更加努力。
2. (用于劝告、建议等) 应该，该
You ought to start at once你应该立刻出发。
Such things ought not to be done.这种事不应该干。
3. (表可能性) 总应该，理应
Mary ought to be home by now.玛丽这会儿该是到家了。
There is a fine sunset. It ought to be a fine day tomorrow.今天有晚霞，明天应该是个好天。
It ought to be a fine day tomorrow morning.明天旱晨大概是个好天气。
4. “ought to + have + 过去分词”表示过去应做某事而实际未做。
You ought to have told me about this earlier.(But you didn't)
你本来应该早一点把此事告诉我。（但没有）
I ought to have written that letter yesterday.(But I didn't)
我本应该昨天写那封信。（但我没写）
It ought to have been done long ago.这事早该做完的。
5. 4.Ought to 在间接引语中表过去时形式不变，如：
He said you ought to tell the police. 他说你应该去报告警察。
3. 形式梳理：
（1）否定式：ought后直接加not，可缩写为oughtn't。
One ought not (oughtn't) to cross the street against the red light.
不应该闯红灯过马路。
（2）疑问式：把ought提到句首。
—Ought we to do it at once? 我们应该立刻做吗？
—Yes, you ought to. 是的。
（3）反意疑问句：下面两种形式都可以：
He ought to be here now, shouldn’t (oughtn’t) he? 他现在应该在这里，是吧？
should和ought to的区别
1. 两者常可换用，ought to语气稍重。
You shouldn’t / oughtn’t to speak to your mother like that.你不应当这样和你妈妈说话。
2. 表示出于法令规则、行为准则、道德责任等客观情况而“应该”做某事时，常用ought to。
Such things ought not to be allowed. 这类事不该容许。
You are his father. You ought to take care of him.你是他父亲,应该照顾他。
3. 表示主观看法、建议、劝说或表示某件事宜于做时，常用should。
You should listen to the doctor’s advice if you want to recover soon.
如果你想很快康复，就应该听医生的劝告。
We should not use too many big words in our everyday speech.
在日常生活中我们不宜于用太多的大词汇。
4. ought to更多反映客观情况，表示“有义务”或“必要”做某事。
You don’t look well. You ought to go to see the doctor.
你气色不好，应该去看病。
5.should可以用于虚拟语态或状语从句中，而ought to 不能。
If I were you, I should try to get there before five.
如果我是你，我会设法五点前到达那里。
(2018湖南模拟) Carol Harvey suggests that cyclists should be asked to ride on their own lanes.
卡罗尔·哈维建议骑自行车的人应该被要求在自己的车道上骑车。
6. should可以是shall的过去式，尤其在间接引语中，用于第一、三人称，以征求对方意见。
He asked me if he should get his visa tomorrow. 他问明天能否拿到签证。
7. should可以表示说话人的特殊情感，如惊奇、愤怒、失望等。
I’m sorry that this should have happened. 我很遗憾竟然发生这种事。
I’m surprised that he should say so. 他竟这样说，这使我很惊讶。
Why should you think that way? 你为什么会那样想？
must, have to和should／ought to表示的不同语气
钢琴老师对某学生说：
You must practice at least an hour a day. (must 显示了老师的权威。)
这个学生然后对他的朋友说：
I have to practice an hour a day!
(have to表示我本身不想练，但迫于老师的压力或者想学会的需要，不得不练。)
他的朋友会说：
You ought to／should practice for more than an hour.
(表示不是来自外界的权威或压力，而是来自平辈同学或朋友的建议或者有义务做。)
易考点：表示推测的情态动词
【情态动词 表推测的情态动词】
1. 肯定推测: 用must, may, might。
注意：must/may/might have done 一定/可能已经做过（表示对过去的推测）
He must be the new teacher. 他一定是那位新老师。
They must have come from Shanghai. 他们一定是上海来的。
They may/might have had a cold. 他们可能感冒了。
补充例句：
He may /might tell his brother, but I am not sure. 他也许会告诉他弟弟，但是我不确定。
(2018 湖南模拟) He must have sensed that I was looking at him. He suddenly glanced at me and said quietly, “Why are you staring at me like that?”
他一定是感觉到我在看着他。他突然看向我轻声问：“你为什么那样盯着我看？”
2. 否定推测：cannot 不可能
cannot/couldn’t have done 不可能做过某事
She cannot be his daughter. She is too old. 她不可能是他的女儿，她年龄太大了。
They cannot/couldn’t have caught the 9:15 train, for they left the hotel at 9:20.
他们不可能赶上9：15的火车，因为他们9：20才离开旅馆。
He can’t have heard us. Knock again. 他不可能听见了。再敲敲门。
3. 否定推测：may/might not 可能不
He may /might not believe you. 他可能不会相信你。
4. 疑问句推测：can/could
What can /could they be doing? 他们会在干什么呢?
Why does he know this? Can /Could someone have told him about it?
他怎么知道? 会是哪个人告诉他了吗?
5. can也可以用于肯定句中，表示理论上的可能性(但实际未必会发生)，或表示“有时”。
Even experienced teachers can make mistakes. 即使是有经验的教师也可能出错。
She can be very unpleasant. 她有时很令人讨厌。
其他情态动词
1. had better 最好
1）had better + 动词原形
2）否定形式：had better not
注意：had better虽然有had，但不表示过去，而是指现在或未来，用于向对方提出劝告或警告。
You had better give up smoking. 你最好把烟戒掉。
You had better not throw it on the ground. 你最好别把它扔在地上。
2. used to 过去常常
1）used to表示过去的习惯动作或状态，现在已不存在。
I used to get up early and take an hour's walk before breakfast.
我过去常常起床很早并且在早餐前散步一小时。
2）在间接引语中，其形式可不变。
He told us he used to play foot ball when he was young. 他告诉我们他小时常踢足球。
3）在疑问句、否定句、否定疑问句或强调句中，可有两种形式：
疑问句：1）将used提前至句首，结构为：Used + 主语 + to do sth...?
2）将did提前至句首，结构为：Did + 主语 + use to do sth...?
Did you use to/ Used you to go to the same school as your brother?
你过去和你弟弟去同一所学校吗？
否定句：usedn’t (usen’t) to/ didn’t use to
I usedn’t to / didn’t use to go there. 我过去不常去那里。
反意疑问句或简略回答中：
She used to be very fat. didn’t she?/ use(d)n’t she?
—Did you use to play chess?
—Yes, I did./ used to.
Used you to get up early in the morning? Yes, I did./ used to.
3. would rather 宁愿
1）表选择，后接不带to的不定式。
I’d rather not say anything. 我宁愿不说任何话。
Would you rather work on a farm? 你更愿意在农场工作吗？
--- Wouldn’t you rather stay here? 你不是宁愿呆在这里吧？
--- No, I would not. I’d rather go there. 不，我不愿意。我宁愿去那边。
(2018 浙江模拟) Usually，gossip spreads information about a topic — breakups，trouble at home，even dropping out — that a person would rather keep secret.
谣言经常传播这样的话题——分手、家里的麻烦，甚至辍学——这些人宁愿保密的话题。
2）would rather…than 宁愿……而不愿……，与……相比，更愿意……
I would rather work on a farm than in a factory. 我宁愿在农场工作也不愿意去工厂。
I would rather watch TV than go to see the film. 与去看电影相比，我宁愿看电视。
巩固练习
选择适当的情态动词
According to the school rule, you ______ walk through the school gate without permission. (mustn’t/ needn’t)
There was a lot of fun at yesterday’s party. You ______ come. Why don’t you? (should/ought to have)
Mother is out. I will ______ stay at home to look after my younger sister. (have to /must)
He is from an English speaking country, so he ______ speak English well. ( can /may)
Finally they ______ escape from the burning building. (were able to / could)
The skyscraper was built on what ______ be a wasteland. (would/ used to)
I can’t believe that! How ______ he be so rude like this! (would/should)
完成下面A、B两项练习
A. ought to1. He ought to help his brother work out the problem. (改成否定句) ___________________________________________________________2．Tom ought to go to have a rest. （改成一般疑问句）______________________________________________________________3．Such things ought to be done at once, _____________？（反意问句）B. 用must, have to, can, ought to, used to和be able to 的适当形式填空。1. In some parts of the world, you ______boil the water before drinking it.2. The bus caught fire seriously, but the passengers ????______escape from it.3. He ______have stayed at home this morning. I saw him shopping in another city.4. You ______ smoke in this part of the hospital.5. You ______keep a simple first aid box at home for any accidents.6. If she is completely well, she ______be back at school today.7. My father ______be a heavy smoker, but now he has given up the habit.8. ------You ______have finished the article. The deadline is last Friday. ------Sorry. I have been busy these days. Could you give me 3 days more?9. She ______ breathe, so I used the mouth-to-mouth way.
10. He ______have caught a bad cold last night, for his forehead felt burning.
完成句子
1. (2018 北京东城期末) 你要是对这个游戏感兴趣，你可以参加到其中来。
If you are interested in the game, ______________.
2. (2018 北京东城期末) 开车的时候，你必须注意交通规则。
While driving a car, ________________ traffic rules.
3. (2018 北京东城期末) 我们应该遵守诺言，这很重要。
It is important_________________.
4. (2018 北京东城期末) 一些演员唱得不够好，他们不得不依靠其他音乐家来帮助他们。
As some actors could not sing well enough, they ____________ other musicians to help them.
5. 我宁可现在就知道这件事，而不是以后。
_____________________ afterwards.
6. 你最好不要错过末班公共汽车。
You ____________ the last bus.
单项选择
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
2. —Guess what! I have got A for my term paper.
—Great! You ______ read widely and put a lot of work into it.
A. must B. should C. must have D. should have
3. 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
4. In crowded places like airports and railway stations, you___ take care of your luggage.
A. can B. may C. must D. will
5. My MP4 player isn’t in my bag. Where I have put it?
A. can B .must C .should D .would
6. 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
7. —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
8. —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
9. As a result of the serious flood, two-thirds of the buildings in the area .
A .need repairing B. needs to repair C. needs repairing D. need to repair
10. I told your friend how to get to the hotel, but perhaps I have driven her there.
A. could B .must C .night D. should
11. The boss has given everyone a special holiday, so we go to work tomorrow.
A．can’t B．mustn’t C．needn’t D．shouldn’t
12. —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
13. —My cat’s really fat.
—You ______ have given her so much food.
A. wouldn’t B. couldn’t C. shouldn’t D. mustn’t
14. —What do you think we can do for our aged parents?
—You ________ do anything except to be with them and be yourself.
A. don’t have to B. oughtn’t to C. mustn’t D. can’t
15. —Turn off the TV, Jack. ____ your homework now?
—Mum, just ten more minutes, please.
A .Should you be doing B. Shouldn't you be doing
C. Couldn't you be doing D. Will you be doing
16. When I was young, I was told that I ______ play with matches.
A. wouldn’t B. needn’t C. mustn’t D. daren’t
17. According to the air traffic rules, you __ switch off your mobile phone before boarding.
A. may B. can C. would D. should
18. — You ought to have called her yesterday.
— Yes, I know I _______.
A．ought to B．ought to have C．ought have done D．ought to have called
19. Why did you keep it a secret from me ? I ____ about it.
A．should be told B．ought to have been told
C．should have told D．ought to be told
20. If he had started at nine o’clock, he _______ have been in London by eleven o’clock.
A．must B．may C．ought to D．has to
21. (2018 北京东城期末) One ought ________ for what one hasn't done.
A. not to be punished B. to not be punished C. to not punish D. not be punished
22. —Is Professor Smith giving the speech today? (2018 北京东城期末)
—It ________ be him. He is abroad right now.
A. mustn’t B. needn’t C. won’t D. can’t
23. (2018重庆模拟) You ____ be Carol. You haven’t changed a bit after all these years.
A. must B. can C. will D. shall
24. You _______ mind your own business.
A．should B．are able C．have to D．had better
25. (2018 浙江模拟) George _________ too far. His coffee is still warm.
A. must have gone B. might have gone C. can’t have gone D. needn’t have gone
答案解析
选择适当的情态动词
1.mustn’t 2.ought to have 3.have to 4.can 5.were able to 6.used to 7.should
完成下面A、B两项练习
A. 1. He ought not (oughtn’t)to help his brother work out the problem.
2. Ought Tom to go to have a rest?
3. ought they?
B. 1. must/have to 2. were able to 3. can’t/couldn’t 4. mustn’t
5. ought to 6. ought to 7. used to 8. ought to
9. wasn’t able to 10. must
完成句子
1. you can take part in it 2. you must pay attention to
3. that we should keep our word 4. had to rely on
5. I’d rather know that now than 6. had better not miss
单项选择
1. C。该题考查的知识点是should的用法。根据对话的意思可以判断，the North Lake应该是很美的一个湖泊，但现在被污染了，言外之意，这个湖泊之美要打上问号。Should这个情态动词有“按理推测”的含义，可译成“理应……”等含义，符合对话的真实意图。will表“现在的自然倾向”，would表“过去习惯、倾向”，must 表“肯定推测”，均不符句意。
2. C。must have done表示“过去肯定做了某事”。should have done表示“本该做某事而没做”。根据上文情景I have got A for my term paper可判断出一定进行了广泛阅读并做了大量工作。所以答案为C项。
3. D。根据下面“否则她是不会在他身上浪费这么多的时间的”可以知道前面的意思是：老师一定是认为在Johnson身上花时间是值得的。must have done表示对过去情况的肯定猜测。
4. C。句意为：在像飞机场和车站这样拥挤的地方，你一定要照看好自己的行李。must表示“必须，一定”，符合句意。
5. A。由句意 “我的MP4不在我包里。我可能把它放哪儿了？”可知应选A。can have done表示“过去可能做过”，而must have done 表示“过去肯定做过”，只能用于肯定陈述句；should have done本应该做（而事实上没做）；would have done只能用于虚拟语气。
6. B。can在此表示能力，can’t表示“不能”。此题所考查的知识点比较简单，但由于句子结构比较复杂，所以许多学生不是由于没有弄清知识点而误选，而是由于不理解句意而误选。全句意为：对于大多数植物来说，它们所面临的最大问题是(有些)动物喜欢以它们为食物，而当它们受到威胁时却不能起身逃跑。
7. C。must have passed the exam表示“肯定是通过考试了”，由前句中的“happy”和下句中的“not difficult after all” 可以推知。
8. D。本题考查情态动词表推测的用法。句意“我的词典哪儿去了？我记得昨天放在这儿了。” “你也许放错地方了”。由句意可以看出是对过去情况的推测，应该用“情态动词 + have done”的形式，故排除A、C两项；should have done sth.意为“过去本该做某事(而没做)”，故排除B项。答案为D项，might have done表示“可能做过某事”。
9. A。句意为：由于猛烈的洪水侵袭，这个地区三分之二的建筑均需要修理。此题作主语的名词为复数形式，谓语动词用复数，need后边应用动名词的主动形式或不定式的被动形式。
10. D。本题考查情态动词。could have done（过去）可能做过；本能够做……；must have done（过去）肯定做过；might have done（过去）可能做过；should have done本应该做（而事实上没做）。由句意“我告诉你朋友该怎么去旅馆，但或许我应该开车送她去那儿。”可知应选D项。
11. C。考查情态动词的否定形式的特定含义。can’t的意思是“不可能”， shouldn’t表示“不应该”，mustn’t 与needn’t的意思大不相同，前者表示“禁止”，意思是：一定不能；后者表示“没有必要”，意思是“不必”，相当于don’t?have?to，从前句“老板放了我们假”，所以“明天没有必要上班”，故选C。
12. C。shall用于第二、三人称，表示命令、允许、警告等，此处表示警告。will表示现在的意志、愿望等，意为“要，希望”；may表示许可，或用于请求许可，意为“可，可以”；must意为“必须，要，应当”。
13. C。根据My cat’s really fat.可以知道是说“本不应该给猫太多食物却给了”所以答案为C。should / oughtn't to have done，意为本来不应做但实际已做，表达遗憾的感彩。
14. A。句意：—你认为我们可以为我们年迈的父母做些什么事？—除了能真心地陪伴他们，你不必做任何事情。don't have to＝needn't“不必”；oughtn't to“不应该”；mustn't“不可以”；can't“不能”。所以答案为A项。
15. B。本题结合交际用语考查should表语气的用法。should可表示惊奇、怀疑、不满等情绪。本题句意：—Jack，关掉电视。你现在不该写作业吗？—妈妈，就看十分钟。情态动词与进行时连用常有表达感彩的功能。故B项正确。
16.C。句子的意思是：当我年轻的时候，（家人）就一直告诫我千万不要玩火柴。must的否定形式mustn’t 表示禁止，意思是“不能，不许”。
17. D。本题考查情态动词的用法。句意“根据空中交通规则，登机前应该关闭手机”，情态动词should在此表示告诉某人应该做什么，故选D。
18. B。简单对话中，只重复助动、系动词和情态动词，如既有情态动词，又有助动词或系动词，则两者都重复，不重复行为动词。
19. B。表示应该做某事，但事实上没做到，应用“should / ought to +不定式的完成式”，本句为被动语态。
20. C。 如果他那时9点开始,就该在11点到伦敦。
21. A。句意：一个人不应该因为他没有做过的事而受惩罚。ought not to 不应该；punish与主语one是被动关系，所以选A。
22. D。根据答语的第二句话可知，史密斯教授刚才出国了，不可能是他演讲，所以选D。否定句中表示推测不能用mustn’t。can’t 不可能。
23. A。从下文的“你这些年一点都没有变”可知选A。must表示可能性很大的推测，表示“一定”。
24. D。句意：你最好管你自己的事。根据句意，选D。had better 最好。
25. C。句意：George不可能走远，因为他的咖啡还是热的。can’t have done表示可能性较大的否定推测，意为“不可能做……”。