情态动词专项讲解1. China is developing its high-speed train technology fast, so it _____begood enough to catch up with the best.A. mayB. mightC. mustD. should2. Then some other interesting reasons appear, such as “It's so smoggythat I ______find my way to office."A. mustn’tB. won’tC. can’tD. shouldn’t3. "The world is big, and I want to see it," wrote a teacher in her resignation letter. _____ you quit your job to travel the worldA. MustB. MightC. ShouldD. Would【答案揭晓】CCD一、情态动词的定义情态动词是一种本身有一定的词义，但要与动词原形或其被动语态一起使用，给谓语动词增添情态色彩，表示说话人对有关行为或事物的态度和看法，认为其可能.应该或必要等。

情态动词后面加动词原形。

1. No driving electric motorbikes in some areas is a rule that we shall obey in Fuzhou.必须.一定（法律.法规等）动词原形2. Women who are exposed to second-hand smoke during their pregnancy can be at risk of abortion.能，会，可以(表示有能力或机会) 动词原形二、常考情态动词的关键用法(一) can1. －Jim，it is time you went to bed．You need to get up early tomorrow.－It’s not f air，Mary can stay up till ten hut I have to go to bed at eight.可以(表示允许)it were not for the fact that she can't sing，I would invite her to the party.能，会，可以(表示有能力)3. Luckily, iron can be reworked and mistakes don't have to be thrown away能够，可以(表示某事物的特点)can be really difficult to get along with at times even though he’s anice person in general.有可能;有时会5. I cannot choose but to go.不能，无法 (用于否定句，表示情况不允许)cannot thank you enough,it has been a wonderful day.再.....也不为过 ( 也可以用can never/hardly.....too much)7.—Is Jack on duty today—It can't be ’s his turn tomorrow.不可能 (can可用于否定句/疑问句中表猜测，此句表对现在的猜测)8.—Can he have been chosen as captain of the football team —Yes, he must have.可能（can可用于否定句/疑问句中表猜测，can have done表示对过去的猜测猜测）9. This old lady was struggling out of the train and I said, 'Oh, can I help you'能 (通常用于疑问句，表示建议或提议帮忙)10. Can you just lift the table for a second(用于疑问句时,can 表示礼貌的请求，而 can't 表示强烈请求）(二) couldmy return journey, I felt I could afford the extra and travel first class 能;会 (表示发生在过去的能力)2.–I feel bored with nothing interesting to do.--You could watch TV. There will be a very good Hollywood film on this evening.可以(表示提议或建议)3. –Could I have a look --Of course you can.表许可（委婉的语气用could，回答时用can）4. An improvement in living standards could be years away.可能(表示某事可能属实或可能发生，对将来或者现在发生事情的肯定猜测)the ship sailed out from Thailand, the 16 sailors on board couldn't have thought_ that only half of可能 (could have done，只用于否定句和疑问句中，表示对过去发生事情的猜测)them would return again. 高.考.资.源.网6. He did not regret saying what he did but felt that he could have expressed it differently.(could have done用于肯定句中，表虚拟语气，表示过去本有可能发生的事情但却并未发生，不能使用 can’t have done的形式)（三）be able toif standardized tests like the SAT could show a stude nt’s academic proficiency（学业水平）,they will never be able to test things like confidence, efforts and willpower, and are unable to give us the full picture of a student’s potentialities（潜力）【解析】be able to 解释为“能够”，有各种时态的形式。

注：can 和be able to 都可以表示能力.can泛指一般的能力,而且只有两种形式,即:can, could．be able to 则主要指具体做到了某件事的能力，其形式主要是靠be 发生变化，所以形式比can 多．可以说：I can swim. I am able to swim.但是不能说：All the people could escape from the big fire in time.只能说：All the people were able to escape from the fire in time.(四) mayone of us may plant a tree in the school, or organize a thorough cleaningon the campus.可以(表许可)2. （1）Some people who don’t like to talk much are not necessarily shy；they may just be quiet people.有可能，也许(may表猜测，用于肯定或否定句中，此例表示对现在某种情况的猜测）（2）You might just as well tell the manufacturer that male customers may not like the design of the furniture.也许，可能(may表猜测，用于肯定或否定句中，may not 为“可能不”的意思)（3）I can’t find my purse anywhere.—You may have lost it while shopping.(may表猜测，may have done表示对过去或者现现在已经完成的动作的肯定猜测) God bless you!祝;但愿(五) mightwas wondering if I might ask you a favor可不可以，能否(用于礼貌地打断别人.提出问题.做出请求或引出接下来要说的话)2.—Excuse this the right way to the Summer Palace —Sorry，I am not it might be.可能(表不是很有把握的猜测，语气比may 弱)3.—Where is my dictionary I remember I put it here yesterday.—You might have put it in the wrong place.(might表猜测，might have done则表示对过去或者现已完成的动作的肯定猜测=may have done)4. I told your friend how to get to the hotel，but perhaps I might have driven her there.（此处，might have done表虚拟语气，意为“过去原本可能/可以做到的事而未做”）holiday isn’t much fun; we might\may as well be back home.只好(做);(做…)也无妨(六) willlow test score, they think, will make it impossible for them to get into a good college.将（表示将来）will carry out these instructions and report back into this afternoon. (表示将来的正式安排)will become her senior adviser--- her deputy, if you will.愿意, answer the phone ------ I will.临时的决定5. Mary will sit for hours reading.The window will not open, however hard he tries.表现在经常反复的动作或者趋向6. Man will die without air.表必然性(七) wouldpromised his doctor he would not smoke，and he has never smoked ever since.（will 的过去式，用于转述）将up! It would be a shame to miss the beginning of the play.She’d be a fool to accept it.将，将会(表示判断或看法)wouldn’t change it even though she knew it was wrong.不愿(表示意愿)he had a problem to solve，he would work at it until he found an answer.常常（表示过去的习惯）She would be always the first to offer to help.The car wouldn’t start this morning.老是，总是（表趋向）(八) shallI shall call you back this afternoon.(表将来用于人称)Has Mr. Tom White arrived --- Yes, already. Shall he wait outside or just come in(shall用在疑问句中，且主语为人称，表示征求对方意见)3.（1）—What does the sign over there read—“No person shall smoke or carry a lighted cigarette，cigar or pipe in this area.”（2）“The interest s hall be divided into five parts，according to the agreement made by both sides，”declared the judge.（3）You shall get the answer tomorrow.（4）They shall not be allowed in after 11 .(shall用在陈述句中，且主语为人称时，表示允诺、命令、警告、决心或规定)(九) should/ought to1.—I think I’ll give Bob a ring.—You should. You haven’t been intouch with him for ages.应该;应当2. (1) —Margaret should not stay at home all day long in front of the TV.应该，必须(表示给出指示或公布官方命令)(2) —That' s right．She ought to go to the fitness center with us.应该，必须should not be any difficulty about passing the road test since you have practised a lot.应该，可能 (表示预期或可能性)you should be fired, your health and pension benefits will not be automatically cut off将要，假定要 (用在虚拟条件从句中表示事件发生的可能性)insisted that we should have a look at every car应该(用在某些动词、名词之后that引导的虚拟语气从句中)6. It’s surprising/strange that he should be a thief.竟然（用在某些adj./n. 之后that 引导的虚拟语气中）7.—I’ll tell Mary about her new job t omorrow.—You should have told her last week.(should have done=ought to have done，表示本应该做的事而未做) oughtn’t to have been late for yesterday’S class meeting，as it was so important．(ought not to have done=should not have done，表示过去本不该做的事却做了)注：ought to与 should的用法区别如下1. 一般说来，两者可替换，只是ought to语气稍重。