1、Unit Four GrammarModal Verbs情态动词,must, might, may, can, could,1. They hold a class meeting every Monday. (a statement of fact)2. They might hold a class meeting every Monday. (the modal verb might expresses a possibility)3. They can not hold a class meeting every Monday. (the modal verb cannot means
2、 that it is not possible for the students to have a class meeting next Monday.)4. They must have held a class meeting yesterday. (the modal verb must have done means that the speaker believes they almost certainly held a class meeting yesterday.),e.g.1. He cant be there. I was there just a few minut
3、es ago. 2. He must be writing his papers in the reading room. 3.Few people may have even heard of Van Gogh.4. Van Gogh couldnt have painted thisits too new.5.Van Gogh worked in an art dealers company, but he must have disliked it, because he left.,情态动词must,may,might,can, could还有表示推测的用法,对当前一般情况的推测： m
4、ust+be+名词/短语/形容词 may/might+be +名词/短语/形容词,用于肯定句,can/could (not)+be +名词/短语/形容词,用于否或疑,A: Can this news be true?B: Yes, it must be true.C: No, it cant be true.D: Yes, it may be true, I think. (Probably it is true.),用于肯或否,情态动词表示推测：对现在（或将来）的动作(状态)的推测：主语+情态动词+动词原形1.The young lady standing there with a book
5、 in her hand must be our new teacher.2.The young girl cant be our new chairman.3. Can / Could the news be true?4. The young lady may/might be our new secretary.,Practice:1. 因为他和Paul长得很象， 所以人们认为他肯定是Paul的兄弟。As he looks like Paul so much,people think he must be Pauls brother.2.既然老师现在不在办公室，那她有可能在教室。Sinc
6、e the teacher is not in the office now, she may be in the classroom.3.从他的表情来判断，他刚才所说的话不可能是真的。Judging from his expression, what he said just now cant be true.,A: What can my father be doing?B: He must be working attentively now. Dont disturb him. （Probably he is working.）,对正在发生的情况的推测： must+be doing 肯
7、定正在做某事 may/might+be doing 也许正在做某事 can/could (not)+be doing不可能正在做某事,1.They must be arguing. But I am interested in what they could be arguing?2. He cant be reading in the room,for I saw him in the street just now.3.隔壁房间很吵，他们肯定正在为他们的女儿举行生日party。As it is noisy in the next room, they must be having a bi
8、rthday party for their daughter.4. 雨下得那么大，他们还会在等我们吗？Since it is raining so heavily, can they still be waiting for us? 5. 他不可能正在打篮球，他肯定在教室。He cant be playing basketball, so he must be in the classroom.,e.g. 1: A: Has Tom arrived? B: No, he may have missed the bus. (Probably he missed the bus.)e.g. 2:
9、 A: Has she got the news? B: I think she can have heard it yet. (Probably she hasnt heard it.),对已经发生的情况或是发生过的事的推测： must+have done 肯定已经做过某事 may/might+have done 也许已经做过某事 can/could (not)+have done不可能已经做过某事,情态动词表示推测：对过去事实的推测：主语+情态动词+have+过去分词1. He couldnt have watched TV yesterday for he knew they would
10、 have an exam. He must have gone over his lessons.2.That might have made him laugh. 3. The road isnt wet. It can not have rained yesterday.4. I dont know why she didnt call me yesterday. Could she have forgotten my telephone number?,Eg1: He must have been writing a long letter to his mother as he ha
11、s been away from home for six months.Eg2: They cant have been waiting in the rain for so long time.,对过去正在发生的情况或是一直持续发生的事情（现在完成进行式）的推测： must+have been doing肯定一直在做某事may/might+ have been doing 也许一直在做某事 can/could (not)+ have been doing 不可能一直在做某事,1.表示劝告和推测，译为“应该”Its nearly seven oclock. Jack should be he
12、re at any moment. If he had had the money, he should have bought it.(虚拟语气）,ought to 和should 的用法：,2.表示责怪，批评（应该做的事情没做）The boys shouldnt be playing football. They should be at school.You should have gone over your lessons.Im feeling sick. I shouldnt have eaten so much ice cream.你上周就应该把你的作文交给老师的。You oug
13、ht to have handed in the your composition last week. 昨天我本来应该送她回家的。但我那时太忙了，没有那么做。I should have taken her home yesterday. But I was too busy then. I didnt do that.,e.g. A:Did you pass the exam. B: No, I should have studied harder.,本来应该做某事，（事实上却没有做）,shouldnt have doneought not to have done,本来不应该做某事，（事实
14、上却做了）,should have done ought to have done,用于对过去的一种婉转的责备:need have done sth. 本来需要做某事，（但事实上没有做）neednt have done sth. 本来不需要做某事，（但事实上却做了）1. It seemed that you need have checked your examination paper more carefully2. The train station is close to us.You need not have hurried there early.,情态动词的几种常见形式：mus
15、t+be+名词/短语/形容词 对现在的一种状态的肯定推测may/might+be +名词/短语/形容词 对现在的一种状态的大概推测can/could (not)+be +名词/短语/形容词对现在的一种状态的否定推测must be doing/cant be doing sth.对现在正在做的长动作的一种肯定/否定推测,情态动词的几种常见形式： must have done sth.肯定已经做了某事（对过去的一种非常肯定的推测） can/could not have done sth.不可能已经做了某事（对过去的一种否定推测） may/might (not) have done sth.也许已经
16、做了某事（对过去的一种大概推测）,情态动词的几种常见形式：should/ought to have done sth.本来应该做某事而没有做(表示一种责备语气) should not /ought not to have done sth.本来不应该做某事而做了(表示一种责备语气) need have done sth. 本来需要做某事而没有做(表示一种责备语气) neednt have done sth.本来不需要做某事而做了(表示一种责备语气),We _ last night, but we went to the concert instead. No wonder we failed
17、in the quiz this morning.A must have studiedB might studyC should have studiedD would study,2. Jenny _ have kept her word. I wonder why she changed her mind.A must B should C need D would3. Michale _ be a policeman, for hes much too short.A neednt B cant C should D may4. My sister met him at the Gra
18、nd Theatre yesterday afternoon, so he _ your lecture.A couldnt have attendedB neednt have attendedC mustnt have attendedD shouldnt have attended,5. I got up early that morning, but I _ so because I had no work to do.A mustnt have doneB didnt need to doC neednt have doneD cant have done.6. It must have rained last night,_?7. He must have been to Hong Kong , for he knows a lot, _?8. You must be a writer,_?A mustnt you B are you C must you D arent you,didnt it,hasnt he,
