第十五节 情态动词和虚拟语气.docx

1、第十五节 情态动词和虚拟语气第十五节 情态动词和虚拟语气【课前预习知识梳理】预习思考题1. 情态动词在句子中的功用是什么？2. 情态动词的基本用法是什么？3. 情态动词+have done怎么使用？4. 虚拟语气一般可用于哪些从句及句式？. 了解情态动词和虚拟语气在英语语法体系中的位置. 主干知识一、情态动词情态动词是一种本身有一定的词义，表示说话人的情绪、态度或语气的动词，但不能单独作谓语，只能和其他动词原形构成谓语。情态动词虽然数量不多，但用途广泛，主要有can/could, may/might, must, need, ought to, dare/dared, shall/should

2、, will/would等，其含义如下。（一）表“推测” 请观察下面的4个句子：1. Where can she have put it? 她可能把它放在哪儿呢？2. Scientists know that cancer may not show up for many years. 科学家们知道癌症可能会很多年不发作。3. The doctor said it will take six weeks and I should be fine by then. 医生说那会花费六个周的时间，到时候我的病就会好了。4. Miss Holloway had a weak heart. She mu

3、st have had a heart attack. Miss Holloway心脏很虚弱，他一定有心脏病。【提示】can, may意为“可能”，should意为“应该”, must意为“必定”,其推测的可能性依次提高。.（二）表“请求”1. 一般性请求对方允许时用May/Can/Could I/we .?Can I take this box out? 我可以把这个箱子搬出去吗？2. 主动提出帮忙或提出建议时用Shall I/we .? Shall I open the door for you? 我替你开开门好吗？（三）表“许可”1. may/can(可以)表示“允许”、“许可”。You

4、 may come if you wish. 想来有你就来。2. should/ought to表示“应该”，shouldnt/oughtnt to表示“不应该”，mustnt表示“禁止”。The new law states that people mustnt drive after drinking alcohol.新法规定人们不能酒后驾驶。3.shall与第二、三人称连用，用于陈述句，表示命令、警告、允诺、威胁；当宣布法律、规定时也常用shall。Will you read me a story, Mummy? 妈妈，你给我读个故事好吗？OK. You shall have one i

5、f you go to bed as soon as possible.好的。如果你尽快上床就能听到。One of our rules is that every student shall wear school uniform while at school. 我们的规定之一就是每个学生在学校里都要穿校服。（四）表“能力” 1. 表现在的能力：can, am/is/are able to 2. 表将来的能力：will be able to 3. 表过去的能力：could, was/were able to, could have done （五）表“需要”、“应该”请观察下面的4个句子：1

6、. I neednt use a clock to wake me up because at six oclock each morning the train comes by my house. 我不必用闹钟叫醒，因为每天早晨六点火车都经过我的房子。2. You dont have to buy a gift, but you can if you want to. 你不必买礼物，但是想买也可以。3. You should take the baby to the doctors. 你应该带孩子去看医生的。 注意：neednt和not have to均可用于表达“不需要”。（六）表“意愿

7、”、“倾向性” 请观察下面的3个句子：1. I have told him again and again to stop smoking, but he will not listen. 我再三告诉他不要吸烟，但他就是不听。（表示意愿）2. John will fall asleep in class. 约翰上课老睡觉。（表示习惯或反复发生的动作）3. Oil will float on water. 油总是浮在水面上。 (用于无生命的事物，表示惯于、总是) 二、情态动词+have done请观察下面的5个句子：1. Jack must have seen the film. 杰克一定看过那

8、部电影。（表示对过去的肯定推测） No. He cant/couldnt have seen it, beause he knew nothing about it. 不，他一定没看过，因为他对此一无所知。（表示对过去的否定推测）2. I shouldnt have watched that movie itll give me horrible dreams. 我不该看那个电影的它会让我做恶梦的。（本不该做但却做了）3. Mark neednt have hurried. He arrived half an hour earlier. 马克没有必要着急的，他早到了半个小时。（做了本没有必要

9、做的事情）4. I didnt know that you were badly short for money then, but you could have asked me for help. 我不知道你如此缺钱，但是你当时应该向我求助的。（本来能够做但却未做）5. What a pity! Considering his ability and experience, he might/could have done better. 真可惜！考虑到他的能力和经验，他当时应该干得更好的。情态动词have done用法must have done一定做过某事，其否定形式为cant/cou

10、ldnt have doneshould/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neednt have done做了本没有必要做的事情can/could have done1.本来能够做但却未做2.可能做过某事may/might have done或许/可能做过某事三、虚拟语气虚拟语气表示说话人的某种假设、猜测、愿望、建议、请求、要求、命令等，而不表示客观存在的事实。通常用动谓语词的特殊形式来表示。（一）虚拟语气在状语从句中的应用1. if条件句请观察下面的3个句子：1) If I were you, I would choose to study

11、further and get a masters degree. 如果我是你，我就会选择继续学习，拿到硕士学位。2) If it had not been for the snow, we could have climbed the mountain as planned. 要不是下学的话，我们就会按计划爬山了。3) If it snowed/ were to snow /should snow hard tomorrow, we would have to put off the game. 如果明天雪下得更大的话，我们就将比赛推迟。从 句主 句与现在相反didwould/should/

12、could/might + do与过去相反had donewould/should/could/might + have done与将来相反didshould dowere to dowould/should/could/might + do注意以下两种情况：1) 错综时间条件句（1) If you had followed the doctors advice, you would be quite all right now. 如果你当时听了医生的建议，现在就全好了。（2) If I were you, I wouldnt have missed the good chance. 如果我是

13、你，我是不会错过哪个好机会的。（3) If they had started in the early morning, they would arrive in half an hour. 如果他们早晨一早动身的话，干个小时以后就回到了。2) 含蓄条件句（1) Without electricity, life could be different. 如果没有电，生活会是另外的样子。（2) But for your help, I wouldnt have made progress. 如果没有你的帮助，我不可能取得进步。（3) I was much too busy then. Other

14、wise I would have replied to your letter. 当时我太忙了，否则的话我就给你回信了。（4) Mary would have attended the party, but she had an unexpected meeting. 玛丽应该参加那个晚会的，但是她有一个预料之外的会。2.其他状语从句1) He acted as if nothing had happened. 他表现得好像什么都没有发生。2) If only he had lain quietly as the doctor instructed, he would not suffer

15、so much now. 要是他像医生要求的那样静静的躺着就好了，就不会受如此多的罪了。3) Mr. Smith spoke so slowly so that he could/ might make himself heard clearly. 史密斯先生说话很慢，以便让别人能听得清楚。4) Even if he had the money, he wouldnt buy it. 他即使有钱也不会买它。（二）虚拟语气在其它句式中的用法1. I wish that the winter holidays would come soon. 但愿寒假很快就到来。2. Would you mind

16、 if I smoked here? 我在这儿吸烟你不介意吧？ Id rather you didnt. 你最好不吸。3. Id rather (that) you had informed me of the news earlier. 但愿你早点告诉我那个消息。4. It is high time (that) we went home. Mum might be worried now. 该回家了，妈妈可能着急了。. 典题剖析1. Are they there? Oh, my goodness. I 69 have put them in there when the phone ran

17、g.（2014年全国卷样题）【解析】根据语境可知，“我一定是在电话铃声响时把它们放在那儿了”，所以用must have done结构，表示对过去发生的事情的一种语气十分肯定的推测。 【答案】must2. A leftluggage office is a place where bags_be left for a short time, especially at a railway station.【解析】该题可能误用will或should。但是该题所设语境是：人们可以把包裹行李放在行李存放处。而should表“应该”，will表意愿，根据句意和语境正确答案为can/may，表示“能够，可

18、以”。【答案】can/may3. My sister met him at the Grand Theatre yesterday afternoon, so he_(attend) your lecture.【解析】该题可能误用shouldnt have attended（表示“责备”）。而对过去发生的动作或存在状态的否定猜测，一般用couldnt have done。【答案】couldnt have attended4. At the meeting, our monitor suggested that we_（have）another discussion about this pro

19、blem.【解析】此题可能误用would have。但suggest表“建议”时其宾语从句用虚拟语气，即为“should动词原形”，should可以省略，但绝对不能用would等词代替。【答案】(should) have【课堂探究双向提能】I. 用情态动词或虚拟语气完成下列句子1. Its surprising that such a gentleman _（竟然那么无礼）to the old.2. Tom must have lost his way, for he hasnt arrived yet.No, he _（一定没迷路）. He has got a map with him.3.

20、 “You _ have a wrong number,” she said. “Theres no one of that name here.”4. If I_（是你）, I would not accept that offer.5. Without your help, I _（取得）progress so rapidly. 6. When a pencil is partly in a glass of water, it looks _（好像断了）.7. But for the help of my English teacher, I _（不会获得）the first prize

21、 in the English Writing Competition.8. If the sun were to rise in the west, my love for you _（不会变）II. 改错并体会情态动词在语句中的功用1. Possible long-term consequences of the “greenhouse effect,” the gradual warming of the Earths climate, may include melting the polar ice caps and a rising sea level._2. The federa

22、l rules aimed at protecting human subjects of medical experiments were established to ensure that patients must be warned of potential risks._. 翻译下面的句子，体会can在不同语境中的不同作用和意义。1. No one can be compared with Yao Ming in playing basketball._2. It can be quite cold here in winter._3. It cant be the postman

23、 at the door. Its only six oclock._4. Can I ask you a question?_5. You cant be serious, Mrs Lorimer?_IV. 翻译下面的句子，比较陈述语气和虚拟语气的区别。1. It looks as if its going to rain._2. Dont handle the vase as if it were made of steel._区别： _V. 把下面的陈述句转化为虚拟语气1. I didnt know about the computer program, so a huge amount

24、 of time and energy was wasted._2. George is going to talk about the geography of his country, but I believe that he should focused more on its culture._3.We were stuck on the way to the scenic spot, so we missed lots of fun there._4. Its really a good chance to go there. But I cant get it._VI. 用本节所

25、学知识破译下列长难句1. (2012辽宁高考阅读C)Some social scientists suggest that westerners should take advantage of the ancient Chinese wisdom to make up for the drawbacks of western philosophy.结构分析:_翻译:_2. (2012湖北高考阅读C)While searching the archives (档案) for information about the universitys higher certificate for women, I was astonished to come across what must be the very letter JexBlake wrote.结构分析:_翻译:_VII. 阅读下面对话，划出里面的情态动词并体会其意义。A: So how long have you known Jack?B: We are old friends. Weve known each other since we