情态动词表推测课件.ppt

1、1,ModalVerbs,2,情态动词 can, could, may,might,must表推测的用法：,情态动词中的can, could, may, might, must都表推测。其中_的可能性最大,_次之,_最小。具体用法如下：1. must的用法（1）表示推测“可能性”时，意思是“_”，语气肯定，有把握。He must be American. =,must,can / could,may / might,一定、准是,It is certain that he is American.,他准是个美国人。,3,（2）must表推测只能用于_。 如表示“一定不、肯定不”的意思时，应用_,

2、 如询问某种可能时，应用_。He must know my address. He cant know my address. Can he know my address?,肯定句,cant,can,他肯定知道我的地址。,他肯定不知道我的地址。,他知道我的地址吗？,He must be a doctor.,他肯定是一名医生。,He cant be a doctor.,Can he be a doctor?,他肯定不是一名医生。,他会是一名医生吗?,4,（3）must表示推测时，可以推测现在/正在发生的动作/过去发生的动作。He must have a car now. He must be

3、doing his exercises in the classroom. He must have finished the work.（过去发生）他一定,（现在）他一定有辆小汽车。,（正在进行）他一定在教室里做练习。,（过去发生）他一定已完成了工作。,5,2. can / could的用法（1）can表示推测“可能性”时，往往用于_或_。Cant“_”，can在疑问句中意思是“_”。He cant be at home. = (2）can /cant+ have done， He cant have gone to Shanghai for I saw him a minute ago.

4、Its so late. Where can she have gone?,否定句,疑问句,一定不,会、可能,It is impossible that he is at home.,他一定不在家。,Can/Could he be at home now?,他不可能去了上海，我刚才还看见他。,天晚了，她可能去哪儿了呢？,表示对过去发生的动作进行推测。,6,(3)could have done e.g I could have done it well，but I wasnt so careful then . (4)can用于肯定句时，多指“客观可能性”,意思是_ e.g Jim is a g

5、ood person,but he can be rude.,本能做但未做,表虚拟语气,我本能提前来,但是我没有赶上公交车.,I could have come here ahead of time, but I missed the bus.,有时会,7,3. may和might的用法（1） may, might表示推测“可能性”时，意思是“_”、“_”He may / might be American. = It is possible that he is American.注：might不表示过去时态，只是语气上比may更委婉，表示的可能性最小。（2）may, might表推测时，可

6、以用于否定句，意思是“_”，但不用于疑问句。He may / might not be at home.,可能,也许,他可能是个美国人。,可能不、也许不,他也许不在家。,8,（3）may, might可以推测现在正在发生的动作或过去发生的动作。He may / might be sleeping now. The boy may / might not be watching TV at home. These students may / might have seen the film before.,这个男孩可能没在家看电视。,这些学生以前可能看过这部电影。,9,1. That man

7、must be Sarahs husband.-No, he_ be her husband. She is still single.A. cant B. mustnt C. may not D. ought to 2. Peter _come with us tonight, but he isnt very sure.A. must B. may C. can D. will,10,5. I saw Mary in the library yesterday.-You_ her. She is still abroad.A. mustnt see B. cant have seen C.

8、 mustnt have seen D. couldnt see 6. David, you _play with the valuable bottle, you_ break it.A. wont; cant B. mustnt; mayC. shouldnt; must D. cant; shouldnt,11,8. Sue_ come together with us tonight, but she isnt very sure yet.A. must B. may C. need D. will,12,情态动词+have+done” 表“本来应该” 使用情况分析,一、should

9、have done过去本来应该 （而实际上并没有) should not have done 本不应该 而实际上却已经” 如：1、We should have studied last night, but we went to the concert instead . 我们昨晚本应学习的，但我们却去看音乐会了。（实际上没有学习）,13,二、could have done 它表示“过去本来能够” 实际上没能做。 如1、I could have run 100 metres in 12 seconds. 我本来能用12秒钟跑完100米的.（实际上没能） 2、If you could have

10、finished the task in time，you could have been promoted. 如果你当时能如期完成那任务的话，你可能已提升了（实际上没有被提升）,14,三、need not have done 它表示过去已做的事，事实上没有必要。 如，1、I need not have got up so early . 我本来不必要那么早起床的（事实上早已起床） 2、I need not have waited for the train for an hour. 我本来不必要等一个小时的火车。 （事实上已经等了一个小时） 问题:,would have done 在什么情况

11、下使用呢?,15,四、would have done 用在虚拟语气中 表示与过去事实相反之假设的结果，常与if 的条件句连用。 1、 I would have helped you if I had known of your difficulties . 要是我当时知道你们的窘境，我就会帮助你了（而实际上没有帮助你） 2、If it hadnt rained yesterday, we would have gone out for a walk .假如昨天没下雨，我们就去散步了。 （实际上没有去）。,16,Practice,1.Mr White _ at 8:30 for the meet

12、ing, but he didnt turn up. A. should have arrived B. should arrive C. should have had arrived D. should be arriving,17,2. If he had been here yesterday, he _ this pop star. A. would meet B. would have met C. met D. must have met,18,3.It is hard for me to imagine what I would be doing today if I_ in

13、love at the age of seven with the Melinda Cox Library in my hometown. A. wouldnt have fallen B. had not fallen C. should fall D. were to fall,19,1）表示肯定的猜测时，各情态动词语气强弱如下：最强must（一定）will （很有可能）would（很有可能）ought to（应该，很有可能）should（应该，很有可能）can（可能）could（可能）may（可能）最弱might（可能）2）表示否定的猜测时cant / couldnt语气最强，指“不可能

14、”；may / might not语气最弱，意思是“可能不”。3)一些情态动词表猜测时的用法限制。must只用于肯定句；may/ might一般不用于疑问句；could可用于各种句式；而can多用于否定句、疑问句，用于肯定句时，多指“客观可能性”。如：Lightning can be very dangerous.闪电可能会非常危险。,20,（3）must表示推测时，可以推测现在/正在发生的动作/过去发生的动作。He must have a car now. （现在）他一定有辆小汽车。He must be doing his exercises in the classroom.（正在进行）他

15、一定在教室里做练习。He must have finished the work.（过去发生）他一定已完成了工作。注：must表示推测时很少用于将来的情况。一般不用He must come tomorrow.可用Its certain / Im sure that he will come tomorrow.,21,（4）在反意疑问句中，当附属部分含有表示推测意义的must时，疑问部分的助动词应与must后面的动词在非推测情况下的用法保持一致。 He must be a worker, isnt he? （现在）他准时个工人，是吗？ You must have learned English

16、for many years, havent you? （完成时）你一定学了好多年英语，是吗？比较： It must have rained last night, didnt it? （过去）昨晚一定下雨了，是不是？He must have arrived by yesterday morning, hadnt he?,22,1）表示肯定的猜测时，各情态动词语气强弱如下：最强must（一定）can（可能）could（可能）may（可能）最弱might（可能）2）表示否定的猜测时cant / couldnt语气最强，指“不可能”；may / might not语气最弱，意思是“可能不”。3)一

17、些情态动词表猜测时的用法限制。must只用于肯定句；may/ might一般不用于疑问句；could可用于各种句式；而can多用于否定句、疑问句，用于肯定句时，多指“客观可能性”。如：Lightning can be very dangerous.,闪电可能会非常危险。,23,“情态动词+have done”不再对一件事情是否发生进行猜测，而是对已发生的事表达自己的看法，有时具有一定的感情色彩。ought to/ should have done本该做（却未做）；oughtnt to/ shouldnt have done本不该做（却做了），含有“责备”之意。如：You shouldnt have done that; I had warned you of that several times.我已多次警告你，你本不该那么