情态动词表推测.doc

情态动词表推测考点1 must have done表示对过去的动作或事实进行推断或猜测，语气最强、把握最大，强调某事的发生是必然的，只用于肯定句中，意思是“肯定、必定、准是”。考例：Tom graduated from college at a very young age.Oh, he _ have a very smart boy then.A. could B. should C. might D. must 答案：D解析：根据上下文可以看出是对过去的事实进行肯定的推测，故选D。考点2 cant/couldnt have donecan与could接不定式完成式均可用在否定句和疑问句中表推测，可看作是must表推测对应的否定形式。如果主句的谓语动词为过去时，表假定或推断的从句必须用couldnt have done,如：We knew he couldnt have crossed the river, because the bridge was broken and there was no boat. (我们知道他不可能过那条河，因为桥断了，而且没有渡船。)考例：My sister met him at the Grand Theatre yesterday afternoon, so he _ your lecture.A. couldnt have attended B. neednt have attended C. mustnt have attended D. shouldnt have attended答案：A考点3 could have done表示过去有能力或有可能做某事，而因某种原因未做，有惋惜、遗憾、批评、责备的意味，如：You could have told me your coming. (你本来该告诉我你要来。)He could have helped me! (他本来可以帮我的。)考例：I stayed at a hotel while in New York.Oh, did you? You _ with Barbara.A. could have stayed B. could stay C. would stay D. must have stayed答案：A解析：由题干答句表疑问的“did you?”可排除D。根据句意：你本来可以和Barbara呆在一起的，可排除B、C,故选A。考点4 should have done用于肯定句表示：（1）根据事物的一般规律所作出的一般推断或推测，如：They should have finished the work by now. (这时他们应该已经完成这项工作了。) （2）表示过去该做的事情没有做，体现了对没做某事的后悔、埋怨、不满、责备、惊奇的情绪，意思是“本来应该”；其否定句表示过去做了不该做的事，意思是“本来不应该却“，如：考例：1）Mr White _ at 8:30 for the meeting, but he didnt show up.A. should have arrived B. should arrive C. should have had arrived D. should be arriving答案：A2）Ill tell Mary about her new job tomorrow.You _ her last week.A. ought to tell B. would have told C. must tell D. should have told答案：D考点5 ought to have done与should have done用法基本相同，一般都能换用，否定形式oughtnt to have done表示做了本来不该做的事。考例：Tom ought not to _ me your secret, but he meant no harm.A. have told B. tell C. be telling D. having told答案：A考点6 may/might have done(1) 用于对过去某事进行推测，表明说话人对过去可能发生的行为或存在的状态的推测。如果主句的谓语动词是过去时，从句必须用might have done,如：He said that she might not have come. (他说她可能还没有来。) (2) 表示某事本来可能发生，而实际未发生也只能用might have done.You might have given him more help, though you were busy.考例：Sorry Im late. I _ have turned off the alarm clock and gone back to sleep again.A. might B. should C. can D. will答案：A考点7 neednt have done只用在否定句中表示过去做了不必要做的事情，意思是“本来没有必要“考例：There was plenty of time. She _ .A. mustnt have hurried B. couldnt have hurriedC. mustnt hurry D. neednt have hurried答案：D考点8