高中英语 破题致胜微方法（情态动词系列）情态动词表推测-可能性的对比.doc

情态动词表推测可能性的对比尽管情态动词的意思众多，但有不少情态动词有一个相同的用法表示推测，也就是表示说话人对某件事情发生的可能性的大小做出判断。这些情态动词表示推测时，语气有强有弱，表示的可能性有大有小。本节课老师就从“推测语气”和“时态”两方面来进行一下总结。一. 情态动词的推测语气肯定语气可能性词义否定语气可能性词义must90%一定cant/couldnt90%不可能should80%应该should not80%按理应该不会may50%可能may not50%可能不could/might25%也许might not25%也许不备注：以上数字并不是绝对的，只是为了让同学们更直观的理解情态动词所表示的确定程度。1. youve had no sleep for 48 hours. you must be exhausted.（非常有把握的推测）你48小时没有合眼了。你一定筋疲力尽了吧。2.he is the best runner, so he should win the race. （较有把握的推测）他是最佳的跑步运动员，所以应该能赢得这次比赛。3. helen may go on the trip with us but she isnt quite sure yet. helen也许会和我们一起去旅行，但她还没拿定主意。（不太有把握的推测）4. he might be sick. i dont really know. he could be at home watching tv. （很没有把握的推测，只是提供一种可能性）他有可能生病了，但我真的不确定，他也有可能在家看电视呢。5. it cant/couldnt be the headmaster. he has gone to america. （非常有把握的推测） 这不可能是校长，他去美国了。6. there shouldnt be any difficulty about passing the road test since you have practised a lot in the driving school. （较有把握的推测）既然你在驾校练习过许多，通过这次驾照考试按理应该没问题。7. -is john coming by train? （不太有把握的推测）-he should, but he may not. he likes driving his car. 他应该是，但也许不是，他喜欢开他自己的车。8. she might not like the idea（很没有把握的推测）她或许会不赞成这个想法。二. 典型例题1. are you coming to jeffs party?im not sure. i_ go to the concert instead.a.must b.wouldc.should d.might答案：d解析：由答语中的 “im not sure” 可知这里表示的是一种不确定的推测，从推测语气上看，might的语气最弱，用在此题中比较合适。must意为“一定”表示的是非常有把握的推测；should表示推测时，意为“照说应该”，也表示很有把握的推测；所以must和should用在此题中不合适。would意为“愿意，常常”句意：你会来jeff的聚会吗？我不确定，我可能会去听演唱会。2. since nobody gave him any help, he _ have done the research on his own.a. mayb. mustc. mightd. need三. 总结1. 熟记情态动词表示推测时，可能性的大小肯定句：mustshouldmaycould/might否定句：cant/couldntshouldnt may notmight not2. 特殊用法mustnt不表示推测，意为“禁止”四. 巩固练习1.【2016天津】it was really annoying; i _ get access to the data bank you had recommended.a. wouldntb. couldntc. shouldntd. neednt2.【2016浙江】george _ too far. his coffee is still warm.a. must have goneb. might have gonec. cant have goned. neednt have gone3. 【2015重庆】you _ be carol. you havent changed a bit after all these years.a. mustb. canc. willd. shall4. 【2015陕西】you _ feel all the training a waste of time, but im a hundred percent sure later youll be grateful you did it.a. shouldb. needc. shalld. may5. 【2013北京卷】-you neednt take an umbrella. it isnt going to rain.-well, i dont know. it _ do.a. mightb. needc. wouldd. should6. 【2013年天津卷】no one _ be more generous; he has a heart of gold.a. couldb. mustc. dared. need7.【2013年安徽卷】it _ be the vocabulary that caused you the problem in the exercise because you know a lot of words.a. mayb. couldntc. shouldd. neednt8. the man in the distance _ be mr. smithhe left for hong kong this morning.a. cantb. mustntc. needntd. wont9. 【2011年江西卷】it _ be the postman at the door. its only six oclock.a. mustntb. cantc. wontd. neednt参考答案与解析：1. 答案：b2. 答案：c3. 答案：a4. 答案：d5. 答案：a解析：根据语境可知,此处表示一种可能性不大的推测, 因此应用might一词,意为“可能,或许”.故答案选a.句意：你没必要带伞,不会下雨的.哦,我不知道,可能会下雨.7. 答案：b解析：考查情态动词.根据后半句“because you know a lot of words”可知,前半句表示否定推测,由此可知,答案b正确.couldnt意为“不可能”；.may表示推测时语气最弱,意为“可能”; should应该; neednt不必要,均不符合语境,故排除.句意：练习中的这个问题不可能是由词汇量匮乏引