1、“情态动词+be doing”的用法“情态动词+be doing”的用法1、推测或评论某动作是否正在进行Our teacher must be correcting our exam papers.我们的老师想必在批改试卷。He cant be working now.他不可能正在工作。We may be playing tennis at nine tomorrow.明天九点我们可能在打网球。2、表示“即将；将要”这类意思I must be going now.我现在必须走了。She may be leaving tomorrow.她可能明天离开。3、用来表示“老是做某事”If you re
2、ally want yourself to be in good health, you must not always be smoking so much.如果你想要一个好的身体，就不该老是抽这么多烟。Why should you always be finding fault with that girl?怎么老是找那个姑娘的岔子?Sir, you oughtnt to be sitting in the waiting room. It is for women and children only.先生，你不该总是坐在这个等候室，这里是妇女儿童专用。情态动词 would 的用法讲解（1
3、）would 是 will 的过去式，表示过去时间的意志、意愿、决心，用于各种人称。They said they would help us.他们说他们愿意帮助我们。I promised that I would do my best. 我承诺我决心尽最大努力。（2）would 表示说话人的意愿或向对方提出请求，语气比 will 婉转，仍指现在时间。Would you like some bananas?你喜欢吃香蕉吗？Id like to see your new bike.我希望看看你的新自行车。Wouldnt it be better to leave tomorrow?明天离开是不是更
4、好？（3）表示过去习惯发生的动作(与 used to 有区别，见 used to)。When he was there, he would go to that coffee shop at the corner after work every day. 他在那里时，他每天下班后都到拐角处那家咖啡店去。The old worker would often go to the park to play chess.那位老工人过去常去公园下棋。She would come to see me now and then.她时常来看我。（4）表示推测。That would be his father
5、.那大概是他父亲。You would be about 10 years old then.你那时大概 10 岁左右。情态动词 should 的用法讲解should（1）表“劝告、建议”时，可译成“应该”，这时可用 ought to 替换。You should keep your promise.你应该遵守诺言。Young people should learn how to use computers. 年轻人应该学如何应用计算机。（2）表示委婉陈述自己的意见。I should think you are right.我想你是对的。I should advise you not to go
6、now.我劝你现在别走。（3）表示惊异赞叹、忧虑、惋惜、欢欣、不满等情绪。Why should you think so?你为何这样想呢？（不满）Its strange that it should be so hot today.很奇怪，今天怎么这么热。（惊奇）Its wonderful that you should have achieved so much in these years.这几年你们有了这样大的成绩，真了不起。（赞叹）（4）表推测意为“可能，该”，表示对现在情况、将来情况的推测。They should be home by now.他们现在应当到家了。The book y
7、ou need should be in our library.你需要的那本书我们图书馆应该有。Its nearly seven oclock. Jack should be here at any moment.现在快要七点了，杰克随时会到。-When can I come for the photos? I need them tomorrow afternoon. 我什么时候能取照片？明天下午要用。- They should be ready by 12:00.明天 12 点前应该能冲好。（5）“should+完成时”，在肯定句中，表示应完成而实际未完成的事情；如果用在否定句中，则表示
8、发生了不应当发生的事件。I told Sally how to get here, but perhaps I should have written it out for her.我和萨丽说了怎样来这里，或许我应该给她写清楚。You should have stopped at the red light.你见了红灯本应该停车。（未停）You should not have gone back to work without the doctors permission.你未经医生许可不应该回去工作的。（回去了）dare 的用法讲解dare 作情态动词表示“敢”，主要用于否定句、疑问句和感叹
9、句，无词形变化，单数第三人称不加-s。（1）通常用于否定句和疑问句，其用法同其他情态动词。She darent even look out.她甚至不敢向外看。Dare you go to school by yourself?你敢独自一人去上学吗？How dare you say I am unfair?你怎么敢说我不公平!I dare not sleep in that room again.我再也不敢睡在那房间了。（2）dare 在下列情况下，也用于肯定句中。句子含有否定意义或疑问意义时。I hardly dare think of it.我简直不敢想这事。He asked me whet
10、her I dare swim across the river.他问我是否敢游过河。I wonder how he dared say that to the teacher.我不知道他怎么敢那样和老师说话。在简略答语中。You darent climb that tree, dare you?你不敢爬那棵树，对吗？Yes , I dare. 不，我敢。状语从句中。I wont allow you to swim across the river, even if you dare do it.即使你敢，我也不愿你游过河去。（3）dare 既表现在和将来，也表过去。Alice was afr
11、aid and dare not go. 艾丽丝害怕，不敢去。注意：从上下代看不出具体时间时，通常不用情态动词 dare，而用实义动词的过去时。She dared to go.她敢去。She didnt dare(to)go.她不敢去。used to 与 would 的区别讲解情态动词 used to 和 would 都可以表示过去的习惯性动作，但有下列不同点：used to 表示确定的过去时间，不需与确定的过去时间连用，而 would 一般与时间状语连用。used to 含有与现在相比较的意思，而 would 没有。He used to get up early.他过去常常早起。(现在不早起
12、了)The old man would go to the park every day to have morning exercises.那位老人以前每天都去公园晨练。（没有与现在相比较的意思）used to 指过去反复发生或持续发生的动作，而 would 仅指过去反复发生的动作，不指持续发生的动作；另外，used to 既表动作还表状态，而 would 只表动作不表状态，因此下列句中的 used to 不能用 would 代替。People used to think that the earth was flat.人们过去认为地球是平的。She used to be very nerv
13、ous in the exam.她以前考试常常很紧张。used to 表客观事实，would 则表示一种意愿。When he lived by the sea, he used to suffer diseases.他住在海边时，经常有病。（used to 不能换成 would）There used to be a small village here.这里曾经有一个小村庄。used to 用法讲解 used to 只有一种存在形式,一般过去式。具体用法如下：（1）在肯定句中，表示现在己经不再发生，不复存在的过去的行为或存在的状态。He used to smoke 20 cigarettes
14、a day.他过去每天抽 20 支烟。There used to be a building there.那里曾经有座大楼。（2）used to 通常只能跟不定式，但偶尔也能跟进行时，意思一样。He used to be always making jokes.他过去总爱开玩笑。（3）在疑问句、否定句或强调句中，可以有两种形式：Used you to go to work by bike?Did you use to go to work by bike?你过去常骑车上班吗？He usednt to smoke as much as he does now.He didnt use to sm
15、oke as much as he does now. 他过去不像现在抽这么多烟。I certainly used to play football, but it was a long time ago.I certainly did use to play football, but it was a long time ago.我过去的确常踢足球，但那是很久以前的事了。（4）在反意疑问句或简略回答中，也有两种形式：John used to be very fat, didnt he/usednt he?约翰曾经很胖，是吗。Used you to live in Shanghai?你过去曾住在上海？Yes, I did/ I used to.是的。
