情态动词PPT.ppt

1、,情态动词,Modal verbs,1 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 ，cant或couldnt 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

2、 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 Amustnt Bcant Cshouldnt Dmay not,2. Peter come with us tonight，but he isnt very sure yet Amust Bmay Ccan Dwill,2)may和might都不用于疑问句中。,3. Are you coming to Jeffs party I

3、m not sure I go to the concert instead Amust Bwould Cshould Dmight,4. It _ last night，for the ground was wet this morning Amust have rained Bmay have rained Cmust rain Dmight 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

4、hand? He _ be glad toHe never refused our request Acan Bmust Cmay Dshould,2. When can I come for the photos? I need them tomorrow afternoon. They _ be ready by 12：00 Acan Bshould Cmight Dneed,3. Its nearly seven oclockJack _ be here at any moment Amust Bneed Cshould Dcan,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

5、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，might。,2 情态动词表示能力的用法,情态动词表示能力时，一般用cancould或be able to,3. 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. c

6、an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.,3 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ma

7、y，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 mustnt. Please dont. 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 begi

8、n 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),shall和should,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

9、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: Ill 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 to,must 必须，侧重说话人

10、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 neednt. No, you dont have to.),注意：,mustnt 不应该，不许，禁止,neednt不必,dont have to,1. 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.,will做情态动词,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