1、情态动词完成时的用法1、语法特点：英语中的情态动词既没有人称的变化，也没有数的变化，但有时态的变化。常见的时态主要有一般式、过去式、进行式和完成式。其中完成时是较难的一种时态形式，其动作主要表过去的行为，它的结构是“情态动词 + have + 过去分词” ，每个情态动词的完成时的含义不同。例如：1) Last night he must have been out, for the light in his room was not on.昨晚，他一定出去了，因为他房间里没亮灯。2) You shouldnt have beaten him. After all he is a child.你
2、不应该打他，他毕竟还是个孩子。3) He may / might have read the book. 他或许读过那本书了。2、用法归纳：1) must + have done：用于肯定句，表示推测，意为“一定 (已经)”。例如：You must have mistaken my intention. 你一定是误会了我的意图。2) can + have done：用于否定句或疑问句，表示推测，意为“可能( 已经)”。例如：He cant have left so soon. 他不可能走得这么早。3) could + have done：可用于肯定句、否定句或疑问句，表示推测、责备或遗憾等，意
3、为“可能”、 “本来可以 ”、 “本来应该”等。例如：We could have walked to the station , for it was so near .我们本来是可以走到车站去的，因为路很近。4) should ought to + have done：可用于肯定句、否定句或疑问句，表示责备或遗憾等，意为“本来应该 ”。例如：(1)You should/ ought to have started earlier , but you didn”t. 你本应该早一点出发，但是你没有。(2) We shouldnt/ ought not to have waited for he
4、r because she never came.我们本不应该等她，因为她根本不会来。5) need + have done：用于否定句或疑问句，用于否定时意为“本来不必” ，用于疑问句时意为“有必要 吗?”。例如：You neednt have told him the news. 他本来不必把这个消息告诉他。6) may + have done：用于肯定句或否定句，表示推测，意为“可能(已经)”。例如：If we had taken the other road , we may have arrived earlier. 如果我们选择另一条路，我们可能会到得早一些。7) might +
5、have done：用于肯定句或否定句，表示推测，意为“可能( 已经)(此时 might 可换为 may)；另外还可以表示过来可能发生的事结果未发生，意为“本来会”(此时 might 不能换为 may)。例如：I might have come to a wrong conclusion. 我或许得出了错误的结论。二、巩固提高I. Fill in the blanks, using the proper modal verbs neednt, would, May, mustnt, wont.1. Dont forget to bring my new book to me tomorrow
6、afternoon. No, I _.2. I hear youve got a set of Australian coins. _ I have a look? Yes, certainly.3. He seldom listens to others. He _ answer for what he has done.4. May I leave the office before 5oclock in the afternoon? No, Im afraid you _.5. Shall I tell John about it? No, you _. I dont know II.
7、Translate the following into English, using the perfect tenses of the modal verbs.1. 他不可能离开得这么早。_.2. 我本应想到这一点的。_.3. 你没有必要提及此事的。_.4. 你准是错拿了我的雨伞。_.5. 我本不应该像那样对我父亲说话的。_.III. Choose the best answer.( ) 1.He doesnt have to work tomorrow, but you have got to, _ you?A.dont B.havent C.havent got D.cant( ) 2
8、.You _ wake me up when I fall asleep, _ you?A.havent better; have B.would not rather; wouldC.had better not; should D.had not better; must( ) 3.-Why! I couldnt get you on the phone this morning.-We _ tennis in the yard when you phoned me.A.could be playing B.must be playing C.must have been playing
9、D.should have played( ) 4.-We didnt see him at the lecture.-Neither did anybody else. He _ it.A.may not have attended B.mustnt attend C.cant have attended D.couldnt attend( ) 5.-I came here by taxi and the driver charged me 50 yuan.-Really? You _ have come by bus.A.could B.must C.may D.should( ) 6.-
10、Do you still remember when we went to the Great Wall?-I cant remember it well, but _ it have been sometime last May?A.should B.must C.could D.would( ) 7.-I wonder why Mr Lin didnt come to work.-He _ have been ill.A.neednt B.should C.might D.can( ) 8.-No one passed the mathematics examination today.-
11、I guess we _ the exercises last night.A.could review B.should review C.might review D.should have reviewed ( ) 9.She _ the hospital so soon, for she hasnt yet recovered.A.wouldnt have left B.shouldnt have left C.neednt leave D.hadnt left( )10.Why didnt you tell me there was no meeting today? I _ all
12、 the way here through the heavy snow.A.neednt have driven B.cant have driven C.must have driven D.shouldnt have driven三、真题零距离( ) 1.- Sorry, Professor Smith. I didnt finish the assignment yesterday. ( 2010上海)- Oh, you have done it as yesterday was the deadline. A. must B. mustnt C. should D. shouldnt( ) 2. Mark _ have hurried. After driving at top speed, he arrived half an hour early.(2010天津)A. neednt B. wouldnt C. mustnt D. couldnt( ) 3. I _ have watched that movie itll give me horrible dreams. (2010山东)A. shouldnt B. neednt C. couldnt D. mustnt
