1、新牛津高中英语语法讲练八新牛津高中英语语法讲练八情态动词情态动词 情态动词是一种辅助动词，有一定的词义，但意思不完整，要和行为动词的原型构成谓语， 可以进行一般提问、 可以进行一般疑问句的肯定和否定回答。 情态动词表示说话人的看法或 主观设想。如果不是以上用法，就不属于情态动词。 We must learn English well.(must 为情态动词) He must be watering flowers now.(must 不是情态动词) Dare you say I am unfair?(dare 为情态动词) He doesnt dare to go out at night.(
2、dare 不是情态动词) 英语里常见的情态动词有：can, could, may, might, should, ought to, must, shall, will, would, dare, need, have to, used to, had better 等。 1 can 和 could can （1）表示能力，一般译为“能、会，相当于 be able to”，尤其指生来具备的能力。 She can swim fast, but I cant. 她会游泳，但我不会。 注意：在一般过去时里，could 表示能力和很小的可能性，而 was/were able to do 则表示成功 地
3、做某事。 （2）表示许可，在口语中可换 may。 You can use my dictionary. 你可以使用我的词典。 （3）表示推测，译为“可能”，常用于否定句和疑问句中(肯定句中用 must)，此时cant译为 不可能； Can the news be true? 这个消息可能是真的吗？ It cant be our teacher. He is on a visit to the Great Wall. 不可能是我们老师，他在参观长城呢。 It cant have rained last night because the ground is not wet.( cant 可换 c
4、ouldnt, 用 couldnt 更委 婉). 因为地上不湿，昨夜一定没有下雨。(cant/couldnt have done 表示对过去发生事情语气很强 的否定推测；must have done 表示对过去发生事情语气很强的肯定推测) could (1) can 的过去式，译为“能、会”，表示过去的能力。 He could write poems when he was 10 years old. 他十岁的时候就会写诗了。 （2）could 在疑问句中，表示委婉请求的语气，没有过去的意思。 Could you do me a favor? 你可以帮我一个忙吗？ （3）could 在虚拟语气
5、里，表示正话反说、惋惜等语气。 You could finish the task if you did it right away. 如果你马上做，你就能完成这个任务。 Your composition could have been written well if you had written it carefully. 如果你细心写的话，你的文章本可以写得很好。 另外，must have done 的否定和疑问形式只能使用 could have done 的形式来表示。 2 may 和 might may （1）表示请求、许可，比 can 要正式 May I borrow your b
6、ike? 我可以借用你的自行车吗？ You may go home now. 你现在可以回家了。 （2）表示可能性，译为“可能、或许”，一般用于肯定句中。 It may rain tomorrow. 明天可能会下雨。 （3）表示希望、祈求、祝愿，常可译为“祝愿”，通常是用 may+主+动词 May you have a good time! 祝你玩的愉快 May you succeed! 祝你成功！ might （1）might 是 may 的过去式，用于表示过去的可能性；might 也可以用于现在表示可能性， 低于 may，没有过去的意思。 He is away from school. H
7、e might be sick. 他离开学校了，也许是病了。 (2) must have done的语气很强， 如果要表示弱和较弱的语气， 可以把must换成may和might。 His room is locked. He might have gone to town.他的门锁着。他或许进城了。 (3) might have done 还可以用于对过去情况的虚拟，解释为：本可以。如： If you had come ten minutes earlier, you might have asked him for help. 3 must 和 need must （1）must 表示主观看
8、法，译为“必须” You must stay here until I come back. 你必须待在这里，直到我回来。 Must I hand in my homework right now ? 我现在必须要交作业吗？ （2）对 must 引导的疑问词，肯定回答为 must，否定回答为 neednt 或者 dont have to Must I finish my homework? 我必须完成作业吗？ No, you neednt. 不，你不必。 have to=must，have to 表示客观上的必须。如： Its raining heavily now. I have to st
9、ay at home. （3）must 也可以表示推测，译为“一定、肯定”，用于肯定句。 The light is on, so he must be at home now. 灯开着，所以他现在一定在家。 表示对过去的推测，用 must have done，用于肯定句。 It must have rained last night because the ground is wet. 因为地上湿的，昨夜一定下雨了。 （4）否定形式 mustnt 表示禁止、绝不许。 You mustnt play with fire. 你不许玩火。 You mustnt be late. 你不许迟到。 mus
10、t 表示肯定的判断、推测时,反意疑问句的构成形式： 当 must 表示肯定的判断、推测时，其反意疑问句要用实际问句的助动词来构成。 She must have seen the film, hasnt she? 她一定看过这部电影，难道没有吗？ You must have met uncle Wang in the shop yesterday, didnt you? 你昨天一定在商店看到王叔叔了，难道没有吗？ He must be watering the flowers now, is he? 他一定在给花浇水，是吗？ need （1）need 表示需要，主要用于否定句和疑问句中，有时也可
11、以用在肯定句中。其否定形式 neednt 译为不必；用 need 提问时，肯定回答用 must；否定回答用 neednt 或 dont have to； There is only ten minutes left. You need hurry up. Need I stay here any longer? 我需要待在这里吗？ 肯定：Yes, you must.是的，你必须。 否定：No, you neednt./dont have to. 不，你不必。 （2）need 还可以作实义动词(行为动词)，此时有人称、数和时态的变化，如果是人作主语 后边多接动词不定式。 I need to do
12、 it right now. 我需要现在做这件事。 如果是物作主语，一般用 need doing 与 need to be done。这种情况下应注意两点： 1）主动形式的动名词 doing 具有被动的含义； 2）该动名词可以改为其动词不定式的被动形式而句子的意义不变； The door needs painting.=The door needs to be painted. 门需要被油漆。 另外，英语中有一个很有用的短语 neednt have done，表示过去做了本不必做的事情。该短 语只有否定形式。 I neednt have taken my raincoat with me be
13、cause it was sunny yesterday. 昨天天气很好，我本不必把雨衣带在身边。 4 dare dare 译为“敢、敢于”，用法近似于 need，有两种词性。dare 作为情态动词，多用于否定句、 疑问句或者条件句中，只有一般现在时和一般过去时。 Dare he tell them what he knows? 他敢告诉他们他知道的事情吗？ I darent ask her. Will you do it for me? 我不敢问她。你可以帮我问吗？ dare 作为实义动词(行为动词)时有人称、时态、单复数的变化。 He doesnt dare to break his pr
14、omise. 他不敢违背承诺。 5 should 和 shall should （1）should 译为“应该”，可表示劝告、建议、义务、责任、按照常理应该等。在名词性从 句里，should do 还可以表示“惶恐、惊讶”的语气。should 译为“应该”，表示劝告、建议、 义务、责任、按照常理应该等时，可以换成 ought to 或 be supposed to。 We should protect the environment. 我们应该保护环境。 It should be quiet in a hospital. 医院里应该很安静。 Its strange that the girl
15、(should) marry so early. 这个女孩这么早结婚，真令人惊异。 在名词性从句里，should do 表示“建议，惶恐、惊讶”的语气时。should 常省略。 Its important that we (should) read English every day. Its surprising that he (should) not know his mistake. （2）should have done 译为“本应该做某事而没做”，表示对过去动作的责备、批评。 You should have finished your homework yesterday. 你本应
16、该昨天完成作业的。（实际上没有） （3）should have done 还可表示过去就应该做或过去居然做了某事。 He should have taken the chair away without the hosts admission. 没有得到主人的同意，他居然把椅子拿走了。 He should have been at the meeting because he was interested in the issue. 他对这个问题感兴趣，他应该参会了。 should 作为助动词，是“shall”的过去式，表示“将”的意思，主语只能是第一人称。如： We told them th
17、at we should(would) do our best to help them. shall （1）shall 表示征求对方意见，多用于第一、三人称。 Shall we go out for a walk? 我们出去散步好吗？ Shall the driver wait outside? 司机在外面等好吗？ （2）shall 表示承诺、命令的语气时，多用于第二、三人称。 You shall have a present on your birthday. 你生日那天会有个礼物。 When the headmaster comes, no one Shall talk. 校长来时，任何
18、人不许说话。 可以这样总结：shall 作为情态动词，主要表示说话者“承诺、命令、请求”的语气。这种 语气不是句子主语的语气，是讲话者的语气。 6 will 和 would will 表示意愿、意志、打算、总是等意思，可用于各种人称。在一般过去时里，will 变成 would,也表示意愿、意志、打算、总是等意思，也可用于各种人称。尤其 would 表示过去总 是这个意思时，可以和 used to 互换。注意：“will”和“would”解释为“将”这个意思时，不是 情态动词，是助动词，帮助构成将来时。 If its possible, he will talk for hours. 如果可能的
19、话，他会滔滔不绝谈上几个小时。 No matter how hard I push the door. It wont open. 不管我怎么推,门总是不开。 7 had better had better 译为“最好”，没有人称的变化，后面接不带 to 的不定式，其否定形式为 had better not； We had better go now. 我们最好现在去。 had better 可以换成:may as well 或 might as well. 学习情态动词，还要注意以下两点： 一几个“情态动词+have done”的短语，也就是常说的“情态动词的完成式”。 1. can/cou
20、ld/may/might have +done sth. 表示过去， 推测过去时间里可能发生过的事情； 是 must have+done sth 的否定、疑问和语气弱化的表达。 Philip can/could/may/might have been hurt seriously in the car accident. 菲利普在车祸中可能受到很严重的伤。 2.must have+done sth. 对过去时间里发生过的事情的推测，语气强，译为“肯定、一定做过某 事” She must have gone by bus. 她一定是乘公交车去的。 3.should/ought to have d
21、one sth. 本应该做某事，而事实上并没有做，否定句表示“不该做某事 而做了”。 You ought to /should have been more careful in this experiment. 你在试验中本应该更小心的。（实际上没有） He ought not to have thrown the old clothes away. 他本不应该扔掉旧衣服的。（实际上扔了） 4.neednt have done sth. 本没必要做某事却做了 I dressed very warmly for the trip, but I neednt have done so. The
22、weather was hot. 我为了这次旅行穿的很暖和。但是我本没有必要这样做的，天气很热。 5.would like to have done sth. 过去本想做某事而没做 I would like to have read the article, but I was very busy then. 我本想阅读这篇文章的，但是那个时候我太忙了。 二情态动词还可以和主要动词构成进行式和被动式。如： Jack may be reading in the classroom. Lao Wang must be watering flowers in the garden. The road
23、 may be blocked at this time. 巩固练习读下面的故事，在每个空白处填上一个词，注意使用情态动词 Once upon a time there lived a vain Emperor who care for elegant clothes than anything else. He changed clothes almost every hour and loved to show them off to his people. Word of the Emperors habits spread over his kingdom and beyond. Tw
24、o cheats who had heard of this decided to take advantage of it. They introduced themselves at the gate of the palace. We are two very good tailors and after many years of research we have invented an extraordinary method to weave a cloth so fine that it looks invisible. In fact, it is invisible to a
25、nyone who is too stupid and incompetent. The chief of the guards heard the cheats strange story and ran to the Emperor and told him the news. The Emperor decided to see the two cheats. Besides being invisible, your Highness, this cloth will be woven in colors and patterns created especially for you.
26、 The emperor gave the two men a bag of gold coins in exchange for their promise to begin working on the cloth immediately. The two cheats asked for a loom, silk, gold thread and then pretended to begin working. The Emperor thought he had spent his money quite well: in addition to getting a new extra
27、ordinary suit, he (1)_ discover who of his ministers were ignorant and incompetent. A few days later, he called in the old and wise prime minister, who was considered by everyone as a man with common sense. Go and see how the work is going on, the Emperor told him, and come back to let me know. The
28、prime minister was welcomed by the two cheats. Were almost finished, but we need a lot more gold thread. Here, Excellency! Admire the colors, feel the softness! The old man bent over the loom and tried to see the cloth that was not there. He felt cold sweat on his forehead. I cant see anything, he t
29、hought. If I see nothing, that means Im stupid! Or, worse, incompetent! If the prime minister admitted that he didnt see anything, he (2)_ be dismissed from his office. “ Marvelous!”, he said then. Ill certainly tell the Emperor. Finally, the Emperor received the announcement that the two tailors ha
30、d come to take all the measurements needed to sew his new suit. Come in, the Emperor ordered. Even as they bowed, the two cheats pretended to be holding a large roll of cloth. Here it is your Highness, the result of our labour, the cheats said. We have worked night and day but, at last, the most bea
31、utiful cloth in the world is ready for you. Look at the colors and feel how fine it is. Of course the Emperor did not see any colors and could not feel any cloth between his fingers. He panicked and felt like fainting. When he realized that no one (3)_ know that he did not see the cloth, he felt bet
32、ter. Nobody (4)_ find out he was stupid and incompetent. And the Emperor didnt know that everybody else around him thought and did the very same thing. Once the two cheats had taken the measurements, they began cutting the air with scissors while sewing with their needles an invisible cloth. Your Hi
33、ghness, youll have to take off your clothes to try on your new ones. The two cheats pretended to help the Emperor to dress. The Emperor was embarrassed but since none of his bystanders were, he felt relieved. Yes, this is a beautiful suit and it looks very good on me, the Emperor said trying to look
34、 comfortable. Youve done a fine job. Your Majesty, the prime minister said, we have a request for you. The people have found out about this extraordinary cloth and they are anxious to see you in your new suit. The Emperor was doubtful about showing himself naked to the people, but then he abandoned
35、his fears. After all, no one (5)_ know about it except the ignorant and the incompetent. All right, he said. I (6)_ grant the people this privilege. He summoned his carriage and the ceremonial parade was formed. All the people had gathered in the main square, wanting to get a better look. Everyone w
36、anted to know how stupid or incompetent his or her neighbor was. As the Emperor passed, a strange murmur rose from the crowd. Everyone said, loud enough for the others to hear: Look at the Emperors new clothes. Theyre beautiful! What a marvellous train(拖裙)! And the colors! The colors of that beautif
37、ul cloth! I have never seen anything like it in my life! They all tried to conceal their disappointment at not being able to see the clothes, and since nobody was willing to admit his own stupidity and incompetence, they all behaved as the two cheats had predicted. Achild, however, said:The Emperor
38、is naked. Fool! his father shouted, running after him. Dont talk nonsense! He grabbed his child and took him away. But the boys remark, which had been heard by the bystanders, was repeated over and over again until everyone cried: The boy is right! The Emperor is naked! Its true! The Emperor realized that the people were right but could not admit to that. He thought it better to continue the parade under the illusion that anyone who (7)_ see his clothes was either stupid or incompetent. 1.would 2.would3.could4.could5.would6.will7.couldnt
