模块四第二单元grammar and usage.ppt

情态动词Note 2Note 1Modal verbsabilitycertaintypermissionobligationmake requestsmake suggestionsmake offersgive advice能力义务, 责任肯定性允许提出请求提出建议提供帮忙提出意见1 情态动词表示能力的用法 情态动词表示能力时，一般用can／could或be able to3. can 客观上能够；be able to 更侧重于“克服一 定困难”“经过一定努力”“有能力”干某事1. be able to用于表示能力并且可用于各种时态， 而can只有一般现在时和一般过去时两种时态2. can常指现在，较常用；如果只表示能力时， 两者都可用注意：The fire spread through the hotel very quickly but everyone _____ get out． A. had to B. would C. could D. was able to I can/am able to swim.We shall be able to finish the work next week.2情态动词表示推测的用法情态动词must，can，could，may，might都可 用来表示推测 1. must所表示的可能性最大，最有把握，意 为“一定”。

2. can和could主要用于否定句和疑问句中 ， can’t或couldn’t 表示“不可能” 3. may 和 might表示现在或将来可能发生的动作 或情况，主要用于肯定句中，might相对于may 来 说，表示的可能性更小一些 注意：1). 表示猜测，can/could一般不用于肯定 句中，除非是“经验之谈” 如：Anybody can make mistakes． 如：(正) Can ／Could it be cloudy tomorrow ？(误) May ／Might it be cloudy tomorrow ？ 1. Mary ____ be in Paris，for I saw her in the town only a few minutes ago． A．mustn't B．can't C．shouldn't D．may not 2. Peter ＿＿＿＿ come with us tonight， but he isn’t very sure yet． A．must B．may C．can D．will 2)．may和might都不用于疑问句中。

3. — Are you coming to Jeff’s party﹖ ﹖ — I’m not sure． I ＿＿ go to the concert instead． A．must B．would C．should D．might 4. It _______ last night，for the ground was wet this morning． A．must have rained B．may have rained C．must rain D．might rain should也可以用来表示“推测”，意为“可能 ；该”, 相当于be expected to往往指具有 一定的客观根据或根据推理对现在某事发 生的“可能性”进行描述，语气上不如must 强1. — Will Mr Wang offer us a hand?— He ______ be glad to．He never refused our request．A．can B．must C．may D．should 2. — When can I come for the photos? I need them tomorrow afternoon.— They ______ be ready by 12：00．A．can B．should C．might D．need3. It’s nearly seven o’clock．Jack _____ be here at any moment．A．must B．need C．should D．can• 解答情态动词表示猜测的试题时，一 要清楚被猜测的时间，二要清楚有无 客观事实根据。

若有客观事实根据， 则无论是肯定还是否定的猜测，猜测 语气最强且符合时间要求的为最佳答 案；若无客观事实根据，纯凭主观臆 断则猜测语气最弱且符合时间要求的 为最佳答案• 情态动词表示猜测时语气从强到弱的 顺序是：must，should，can，may ，could，might3 情态动词表示“许可”、“允许”的用法 can/could/may/might 过去式could常用于疑问句中，比can更加委 婉，表示礼貌回答时，常用原形can或者 may，不可再用过去式could/might — Could I borrow your dictionary? — Yes, of course you ____． A. might B. will C. can D. should— Can/May/Could I use your pen? 肯定简略回答：— Yes, you can/may.— Yes, please. 否定简略回答：— No, you mustn’t. — Please don’t. — No, you may not. 4 其它情态动词的用法1). shall用于第一、三人称疑问句中，表示 说话人征求对方的意见和向对方请示。

Shall we begin our class?（征求意见）2). shall用于第二、三人称陈述句中，表示说 话人给对方的命令，警告，允诺，决心或威 胁 You shall go with me. (命令) You shall have the book when I finish it. (允诺) He shall be punished. (威胁)When shall Mike be able to leave hospital?(请示)3). 用于条约，规定，规章等文件中， 表示一种义务，多用于第三人称中 “The interest ___ be divided into five parts, according to the agreement made by both sides.” declared the judge. A. may B. should C. must D. shall 4). should= ought to 表示劝告，命令，建 议，意为“应该”，而ought to 语气更强A: I’ll start the work tomorrow.B: I think you should start today.C: No, you ought to start at once.(语气更强）must / have tomust 必须，侧重说话人的主观看法have to (有多种时态）侧重于客观上的需 要，含有“不得不”的意思＝have got to— Must I hand in my exercises now? — Yes, you must. (No, you needn’t.／ No, you don’t have to.)注意：mustn’t 不应该，不许，禁止 ＝needn’t 不必don’t have to1. will表示请求, 建议等, 不如would委婉 Will /Would you pass me the book? Will he pay for me?2. will 表示意志, 愿望, 决心 I will never do that again. I will give up smoking.used to和would的区别1. 都可以表示过去重复的习惯，used to 含 有“过去怎样而现在却不这样了”的意思； 而would则单纯表示过去的习惯性动作，常 和often, everyday等连用。

He would take a walk near the forest in the evening. （现在可能散步也可能不散 步了） He used to take a walk near the forest in the evening. （而现在不散步了）1. She isn’t what she used to be. 她跟过去 不一样了 （表示对比，不可用would） 2. There used to be a park. 以前这里有一 个公园 表示过去的状态，只能用used to，不可用 wouldused to和would的区别可兼做行为动词的情态动词：need 、 dare 情态动词 (+动词原形)行为动词.needdare1.无人称和数的变化; 2.尤其用于： *否定句及疑问句中; *在if/whether之后; *或与hardly, never, no one, nobody连用;3.常以needn’t和daren’t 的形式出现; 4.dare有其过去时dared.多用于肯定句;need to dodare to do need to be doneneed doing — Need I help you? — Yes, please. You needn’t telephone him now.How dare you talk to the teacher like that? The girl dare not go out alone at night.• We need to tell him the news. • You don’t need to tell him the news. • Do the flowers need watering?• I didn’t dare to tell you the truth. • Would you dare to catch the snake with your hand? • The boy dares to do anything he likes.How dare you say such a thing?How dare you to say such a thing?He daren’t to speak English before such a crowd, did he?He daren’t speak English before such a crowd, dare he?Nobody need to be afraid of catching the disease.Nobody need be afraid of catching the disease.These dishes needed be cleaned carefully.These dishes need to be cleaned carefully.These dishes need cleaning carefully.convenient transport: recommended(被推荐的 ) English-speaking citizens: recommended international airport: necessary tourist attractions: recommended parks: optional 随意的 cleanliness: recommended sports stadium: necessary training gro。