Can和could的用法和区别.docx

1、Can和could的用法和区别Can 和 could 的用法和区别?表示能力：能，能够，会He could swim when he was five.?他五岁时就会游泳了。Can you drive a car?你会开车吗？Yes, I can.?我会。No, I cant.?我不会。?表示推测：可能，会I think the work can be completed ahead of time.?我认为这项工作能提前完成。What can he mean?他会是什么意思？注：表示推测时，could不是过去式，只是语气更委婉；若是推测已发生的事或过去的情况，用can/could have加

2、过去分词。如：Today is Sunday. He cant/couldnt be at school.?今天是星期天。他不可能在学校里。Mike cant 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。?表示“有时也会”It can be quite windy there, especially in spring.?那里有时容易刮风,?特别在春季。?表示允许：可以?(口语中常代替may)You can first lend me one book thi

3、s time.?这次你可以先借给我一本书。You cant take the book out of the room.?你不可以将这本书拿出室外。注意：1.?表示允许别人做某事只能用can，不能用could。2.?cant?和?mustnt?一样，都可表示“不准，不允许”。?表示请求：可以Can I go swimming today, please, mum?妈妈，我今天可以去游泳吗？Could you tell me how I can get to the railway station?请告诉我去火车站怎么走吗？注意：could不是过去式，只是语气较can更委婉，注意在回答中不可用c

4、ould。如：Could I have the television on?我可以开电视看吗？Yes, you can. / No, you cant.?可以。/?不可以。can与be able to的比较(1) be able to比can有更多的时态。如：In the past 50 years or so, scientists have been able to “see” farther and farther into the sky.?在过去50年里，科学家们已经能够往天空看得更远。(2)?在表示过去具体某次能够成功做成某事时，只能用was/were able to。如：He w

5、orked very hard and was able to pass that examination.?他学习非常努力他以能够通过了那场考试。一、情态动词can的用法1. 表示能力，意思是：能，会。如：I cant swim.?我不会游泳。Can you drive？?你会开车吗？2. 表示客观可能性，意思是：可以，可能。如：That big cinema can seats 2,000 people.?那家大电影院能坐2000人。He can be very friendly at times.?有时他会很友好。3. 表示允许(和may意思相近)，意思是：可以，能够。如：You can

6、 have the book when I have finished it.?书我看完了可以给你。Can I use your pen？?我可以用你的钢笔吗？4. 表示惊异、不相信等（用于疑问句、否定句或感叹句中），意思是：会，可能。如：This cant be true.?这不可能是真的。Can it be true？?这可能是真的吗？二、情态动词could的用法1. 表示“能力”或“可能性”，作为can的过去形式。如：Could you speak English then？?那时你能讲英语吗？He said he couldnt follow me.?他说他跟不上我。2. 表示惊异、怀

7、疑、不相信等情绪。如：Who could have taken them？?谁会把它们拿走了呢？She couldnt have left so soon.?她不可能这么快就走了。在这种情况下，could和can是可以换用的，用could时口气较缓和，用can时不相信的程度更强一些，两者在时间上没有差别。3. 比较委婉客气地提出问题或陈述看法。如：/PCould you let me have your passport?Yes, here it is.看看你的护照好吗？行，这就是。I could come earlier, if necessary. 如果必要我可以早点来。这时could和c

8、an没有时间上的差别。4. 在虚拟条件句中构成谓语。如：I would certainly do it for you if I could.?要是我能做得到，我一定会为你们做这事儿。How I wish I could go with you!?我多么希望和你们一道去！三、can, could?和?be able to的区别与联系。1. can的过去式是could，但could 除了可作can的过去式外，还可表比can更委婉的语气，因此在回答由could 表示请求的问句中，不能用could，但可用can。如：Could you lend me a hand?Of course I can.2

9、. 在表示现在或过去的智力、体力、技能等方面的“能力”时，can, could 常可与be able to互换。如：/PHe could (or was able to) swim five miles when he was a boy.3. be able to有比can更多的形式，如will be able to，have (has) been able to had been able to 等等。因此be able to常被用来表示can所不能表示的将来或完成的概念。如：/PThey will be able to run this machine on their own in t

10、hree months.?他们过三个月就能自己开这台机器了。4. 在表示成功地做了某事时，不用could，而用was / were able to (或managed to, succeeded in doing sth )来表示。如：He was able to (or managed to) finish the job yesterday。但是couldnt和wasnt / werent able to 常可互换。如：I couldnt / wasnt able to finish the job yesterday.5. 与感觉动词连用时，can，could亦可与be able to互

11、换。如：We could/were able to smell something burning in the kitchen.will与would的用法表示意志或意愿：决心，愿意，好吗？We will do our best to save the child. 我们会尽力抢救这个孩子。I told her to stop crying, but she just wouldnt listen. 我叫她别哭,可她就是不愿听。注：表示请求、建议或征求对方意见时，用Would you? 比用Will you?更婉转。如：Will/Would you please keep the door o

12、pen?请让门开着好吗？Will/Would you go with me?你愿意和我一起去吗?表示真理或习惯：惯于，总是Oil will float on water. 没总是浮在水面上。She will listen to music alone in her room for hours. 他独自在房间里听音乐，一听往往就是几小时。He would get up early when he lived in the country. 他住在乡下时总是早起。表示要求：一定，必须You will report to me afterward. 你稍后一定要向我报告。表示猜测：可能，大概Thi

13、s will be the house youre looking for. 这大概就是你找的那所房子了。I think he would accept the invitation. 我想他会接受邀请的。表示功能：能This auditorium will/would seat one thousand people. 这个礼堂能容纳一千人。would like表示愿意I would like to have a word with you. 我想同你说句话。Would you like a cup of tea? 请你喝杯茶好吗？would ratherthan宁愿也不愿I would r

14、ather fail than cheat in the examination. 我宁愿考不及格，也不愿意考试作弊。would与used to的比较(1) 两者都可以表示过去经常做某事，常可互换。如：When I was young I used to/would get up early. 我年青时经常早起。(2) 下列三种情况要用used to，不用would：强调与现在的对比时；在故事开头时；与be, stay, belong, live, like , think, know等状态动词连用时。如：He doesnt work hard as he used to. 他不像以前那样努力

15、了。We used to swim every day when we were children. We would run down to the lake and jump in我们小时候天天游泳。我们会跑到湖边，跳进水里They used to live here, didnt they? 他们以前住在这里，是不是？(3) 与时间段或与表示“有时”意义的sometimes, at times, now and then, from time to time等连用时，宜用would。如：He would sit like that for hours. 他会像那样一坐就是几个钟。Some

16、times the boys would play a trick on the teacher. 有时孩子们会戏弄老师。has have had?当主语是（I, we, they）时用have,当主语是第三人称he, she, it 时用hashad 是has和have的过去式.用法：1、后接过去分词,构成现在和过去完成、完成进行时.例如：a) He has gone to Beijing. 他已经到北京去了.b) I have been a teacher since then. 从那时起我就一直当教师.c) They had left when I got there. 我到那里的时候,

17、他们已经走了.d) He has been working hard since early morning. 丛一大早他就一直在下劲干活.2、has have had也可以作为一般动词,意为“拥有”“进行”“吃”“使得”“让”等.如果后接不定式,意为“不得不”.因为它们不是特殊动词,所以不能在它们后面加not构成否定句,不能把它们移到句首构成疑问句.例如：a) He has a good pen. 他有一支好笔.b) We have supper at 6:00. 我们六点钟吃晚饭.c) I had my hair cut yesterday. 我昨天理了发.（我让我的头发被剪了,昨天）d)

18、 I have to leave now. 我得走了.of与for的用法以及区别for 表原因、目的of 表从属关系介词of的用法（1）所有关系this is a picture of a classroom（2）部分关系a piece of papera cup of teaa glass of watera bottle of milkwhat kind of football，american of soccer？（3）描写关系a man of thirty 三十岁的人a man of shanghai 上海人（4）承受动作the exploitation of man by man人对

19、人的剥削。（5）同位关系it was a cold spring morning in the city of london in england（6）关于，对于what do you think of chinese food？你觉得中国食品怎么样？介词 for 的用法小结1. 表示“当作、作为”。如:i like some bread and milk for breakfast. 我喜欢把面包和牛奶作为早餐。what will we have for supper? 我们晚餐吃什么?2. 表示理由或原因,意为“因为、由于”。如:thank you for helping me with

20、my english. 谢谢你帮我学习英语。thank you for your last letter. 谢谢你上次的来信。thank you for teaching us so well. 感谢你如此尽心地教我们。3. 表示动作的对象或接受者,意为“给”、“对 (而言)”。如:let me pick it up for you. 让我为你捡起来。watching tv too much is bad for your health. 看电视太多有害于你的健康。4. 表示时间、距离,意为“计、达”。如:i usually do the running for an hour in the

21、morning. 我早晨通常跑步一小时。we will stay there for two days. 我们将在那里逗留两天。5. 表示去向、目的,意为“向、往、取、买”等。如:lets go for a walk. 我们出去散步吧。i came here for my schoolbag.我来这儿取书包。i paid twenty yuan for the dictionary. 我花了20元买这本词典。6. 表示所属关系或用途,意为“为、适于的”。如:its time for school. 到上学的时间了。here is a letter for you. 这儿有你的一封信。7. 表示

22、“支持、赞成”。如:are you for this plan or against it? 你是支持还是反对这个计划?8. 用于一些固定搭配中。如:who are you waiting for? 你在等谁?for example, mr green is a kind teacher. 比如,格林先生是一位心地善良的老师。一. in,on在方位名词前的区别?1. in表示A地在B地范围之内。如： Taiwan is in the southeast of China.?2. on表示A地与B地接壤、毗邻。如： North Korea is on the east of China.?表示方

23、位的名词east(东),west(西), south(南), north(北)等前面都能用表示方位的介词in, on和to,那么这三个介词的用法：?I. in the+方位名词指的是小范围在一个大范围的里面,表示在某范围之内,强调两者的包含关系。如: Beijing is in the north of China. 北京在中国的北部。?II. on the+方位名词指的是一个范围紧挨着另一个范围,表示两地接壤,强调两者为相邻关系。如: Korea is on the northeast of China. 朝鲜在中国的东北面。?III. to the+方位名词指的是一个范围和另一个范围之间隔

24、段距离,表示在某范围之外,强调两者是远离关系。如: Japan is to the east of China. 日本位于中国的东边。二. at, in, on在表示时间上的区别?1. at指时间表示：?（1）时间的一点、时刻等。如：?They came home at sunrise （at noon, at midnight, at ten oclock, at daybreak, at dawn）（2）较短暂的一段时间。可指某个节日或被认为是一年中标志大事的日子。如：?He went home at Christmas （at New Year, at the Spring Festiv

25、al, at night）.?2. in指时间表示：（1）在某个较长的时间（如世纪、朝代、年、月、季节以及泛指的上午、下午或傍晚等）内。如：in 2004, in March, in spring, in the morning, in the evening, etc?（2）在一段时间之后。一般情况下，用于将来时，谓语动词为瞬间动词，意为“在以后”。如： He will arrive in two hours.?谓语动词为延续性动词时，in意为“在以内”。如： These products will be produced in a month.?注意：after用于将来时间也指一段时间之后

26、，但其后的时间是“一点”，而不是“一段”。如：?He will arrive after two oclock.?3. on指时间表示：?（1）具体的时日和一个特定的时间，如某日、某节日、星期几等。如：? On Christmas Day（On May 4th）, there will be a celebration.（2）在某个特定的早晨、下午或晚上。如： He arrived at 10 oclock on the night of the 5th.?（3）准时，按时。如： If the train should be on time, I should reach home befor

27、e dark.?三. at, in和on表示地点时的区别?1. at表示地点：?（1）用于指较小的地方。如： I shall wait for you at the station.?（2）用于门牌号码前。如： He lives at 115 Zhongshan Road.?2. in表示地点：?（1）用于指较大的地方。如： He lives in Shanghai.?（2）虽然是很小的地方，如果说话人住在那里，也可用in。商店、学校、机关等，若看作一个地点（point）用at，若看作一个场所（place）用in。如： I met him at the post-office.?Im now

28、working in the post-office.?3. on表示地点，一般指与面或线接触，意为“在上；在旁”。如：?The picture was hanging on the wall. New York is on the Hudson River.With是个介词，基本的意思是“用”，但它也可以协助构成一个极为多采多姿的句型，在句子中起两种作用；副词与形容词。?with在下列结构中起副词作用：?1.“with+宾语+现在分词或短语”，如：?(1) This article deals with common social ills, with particular attentio

29、n being paid to vandalism.?2.“with+宾语+过去分词或短语”，如：?(2) With different techniques used, different results can be obtained.?(3) The TV mechanic entered the factory with tools carried in both hands.?3.“with+宾语+形容词或短语”，如：?(4) With so much water vapour present in the room, some iron-made utensils have bec

30、ome rusty easily.?(5) Every night, Helen sleeps with all the windows open.?4.“with+宾语介词短语”，如：?(6) With the school badge on his shirt, he looks all the more serious.?(7) With the security guard near the gate no bad character could do any thing illegal.?5.“with+宾语副词虚词”，如：?(8) You cannot leave the mach

31、ine there with electric power on.?(9) How can you lock the door with your guests in?上面五种“with”结构的副词功能，相当普遍，尤其是在科技英语中。接着谈“with”结构的形容词功能，有下列五种：?一、“with+宾语+现在分词或短语”，如：?(10) The body with a constant force acting on it. moves at constant pace.?(11) Can you see the huge box with a long handle attaching to it ?二、“with+宾语+过去分词或短语”?(12) Throw away the container with its cover sealed.?(13) Atoms with the