Mike can’t have found his car, for he came to work by bus this morning.

　　迈克一定还没有找回他的车，因为早上他是坐公共汽车来上班的。

　　注意：could, might表示推测时不表示时态，其推测的程度不如 can, may。

　　七、情态动词+ have +过去分词

　　1.may(might) have + done sth, can (could) have + done sth　表示过去，推测过去时间里可能发生的事情。

　　Philip may (might) have been hurt seriously in the car accident.

　　Philip can (could) have been hurt seriously in the car accident.

　　2.must have +done sth，对过去时间里可能发生的事情的推测，语气较强，具有"肯定"，"谅必"的意思。

　　--- Linda has gone to work, but her bicycle is still here.

　　---She must have gone by bus.

　　3.ought to have done sth, should have done sth

　　本应该做某事，而事实上并没有做。否定句表示"不该做某事而做了"。

　　You ought to (should) have been more careful in this experiment.

　　He ought not to have thrown the old clothes away.(事实上已扔了。)

　　ought to 在语气上比should 要强。

　　4.needn’t have done sth　本没必要做某事

　　I dressed very warmly for the trip, but I　needn’t have done so. The weather was hot.

　　5.would like to have done sth　本打算做某事

　　I would like to have read the article, but I was very busy then.

　　八、should 和ought to

　　should 和ought to 都为"应该"的意思，可用于各种人称。

　　---Ought he to go?

　　---Yes. I think he ought to.

　　表示要求，命令时，语气由 should(应该)、had better最好)、must(必须)渐强。

　　九、 had better表示"最好"

　　had better 相当于一个助动词，它只有一种形式，它后面要跟动词原形。

　　had better do sth

　　had better not do sth

　　It is pretty cold. You’d better put on my coat.

　　She’d better not play with the dog.

　　had better have done sth表示与事实相反的结果，意为"本来最好"。

　　You had better have come earlier.

　　十、 would rather表示"宁愿"

　　would rather do

　　would rather not do

　　would rather… than…　宁愿……而不愿。

　　还有would sooner, had rather, had sooner都表示"宁愿"、"宁可"的意思。

　　If I have a choice, I had sooner not continue my studies at this school.

　　I would rather stay here than go home. = I would stay here rather than go home.

　　典型例题

　　---- Shall we go skating or stay at home?

　　----Which ___ do?

　　A. do you rather　B. would you rather　C. will you rather　D. should you rather

　　答案B。本题考查情态动词rather的用法，would rather +do sth 意为"宁愿"，本题为疑问句， would 提前，所以选B。

　　十一、will和would

　　注意：

　　1.would like; Would like to do = want to 想要，为固定搭配。

　　Would you like to go with me?

　　2.Will you…?　Would you like…? 表示肯定含义的请求劝说时，疑问句中一般用some, 而不是any。

　　Would you like some cake?

　　3.否定结构中用will，一般不用would, won’t you是一种委婉语气。

　　Won’t you sit down?

　　十二、情态动词的回答方式

　　问句　肯定回答　否定回答

　　Need you…?　Yes, I must.　No,I needn’t

　　Must you…?　/don’t have to.

　　典型例题

　　1.---Could I borrow your dictionary?

　　---Yes, of course, you____.

　　A. might　B. will　C. can　D. should

　　答案C.could表示委婉的语气，并不为时态。答语中of course，表示肯定的语气，允许某人做某事时，用can和 may来表达，不能用could或might。复习： will 与you连用，用来提出要求或下命令。should与you 连用，用来提出劝告。

　　2.---Shall I tell John about it?

　　---No, you ___. I’ve told him already.

　　A. needn’t　B. wouldn’t　C. mustn’t　D. shouldn’t

　　答案A。needn’t 不必，不用。 wouldn’t 将不, 不会的。 mustn’t 禁止、不能。 shouldn’t　不应该。本题为不需要，不必的意思，应用needn’t。

　　3.---Don’t forget to come to my birthday party tomorrow.

　　---______.

　　A. I don’t　B.　I won’t　C. I can’t　D. I haven’t

　　答案B.　will既可当作情态动词，表请求、建议、也可作为实义动词表"意愿、意志、决心"，本题表示决心，选B。

　　十三、带to 的情态动词

　　带to 的情态动词有四个：ought to, have to, used to, be to, 如加上have got to ,(=must), be able to，为六个。它们的疑问，否定形式应予以注意：

　　Do they have to pay their bill before the end of the month?

　　She didn’t use to play tennis before she was fourteen.