as的用法.ppt

1、as用法小结用法小结.一、引导让步状语从句（倒装）一、引导让步状语从句（倒装）1.Strong as he is,he is afraid of pain.2.Slowly as the tortoise walks,it can beat the rabbit.3.Doctor as she is,she cant cure her own disease.4.Try as he does,he never seems able to do the work beautifully.adj./adv+as+S+be/v.n.+as+S+be(句首名词不带冠词句首名词不带冠词)v.+as+S+

2、do/does/did。.二、引导时间状语从句二、引导时间状语从句1、I read the letter as I walked along the river.2.As the wealth of the country increases,more waste will be produced.3.As I was going out the telephone rang.4.Mother was worried because little Alice was ill,especially as father was away.(一边一边一边一边)(随着随着)(正要干正要干突然：同时发生

3、突然：同时发生)(当当时候时候).when/while/as1.She can write only when the baby is asleep.2.My pen dropped on the ground when I was walking in the park.3.I was drawing when he came in.4.We must strike while the iron is hot.5.While we were talking,the teacher came in.6.As I looked,some one came near.7.As I get olde

4、r I get more optimistic.。1、when 引导的从句既可以表时间位置，也可表示一段时间，引导的从句既可以表时间位置，也可表示一段时间，因此从句既可以和瞬间动词因此从句既可以和瞬间动词(arrive,begin,borrow,lend,go,come,leave,stop,finish,die,join)连用，也连用，也可使用持续动词可使用持续动词(be,lie,stay,live,study)；2、while引导的时间状语从句表示时间的延续，即表示一段引导的时间状语从句表示时间的延续，即表示一段时间，而不是瞬间，因此，不能与瞬间动词连用；时间，而不是瞬间，因此，不能与瞬间

5、动词连用；3、as不能分先后，而指并相发生，尤指短动作或事件同时不能分先后，而指并相发生，尤指短动作或事件同时发生。发生。as还可以说明两种正在发展或变化的情况。还可以说明两种正在发展或变化的情况。4、when与与while的另一个区别：的另一个区别：when从句的动作既可以与从句的动作既可以与主句的动作同时发生，亦可先后发生，而主句的动作同时发生，亦可先后发生，而 while从句所表从句所表示主句动作发生在示主句动作发生在while从句所表达的时间段之内。从句所表达的时间段之内。1.A.When you telephoned me,I was drawing a picture.B.The

6、telephone rang while I was having a shower.as用法小结用法小结.三、引导原因状语从句三、引导原因状语从句1.As the weather was fine,we decided to walked to the restaurant.2.Tired as they were,they went to bed as they came back.3.She lied to us because she had to do in order to get a job.辨析：一般来说，辨析：一般来说，as表示听者已知的原因，因而常位表示听者已知的原因，因而

7、常位于句首，而于句首，而because表示听者未知的原因，因而常位表示听者未知的原因，因而常位于句尾，成为信息的焦点。因此，于句尾，成为信息的焦点。因此，as不能回答不能回答why的的问题，也不能在强调句型中作为被强调的成分。问题，也不能在强调句型中作为被强调的成分。as用法小结用法小结.三、引导方式状语从句三、引导方式状语从句1.When at Rome,do as Romans do.2.I have changed it like you suggested.3.Please try to write as I do/like me.辨析：做辨析：做“如如”“像像”“按照按照”解的解的a

8、s可用作连可用作连词，其后可引出方式状语，在正式英语里词，其后可引出方式状语，在正式英语里like只能做只能做介词不能做连词。当介词不能做连词。当as和和like都做介词时，词义不同，都做介词时，词义不同，as表示表示“作为作为”以以资格资格“”，like则表示则表示“像像”“与与相似相似”as用法小结用法小结.四、四、asas表示倍数的句型表示倍数的句型1.Tom is as tall as I.2.Jack is not as/so clever as his sister.3.This pencil is half(a quarter)as long as that one.4.Soun

9、d travels nearly five times as fast in water as in air.A is n times as much(large,great,fast,many)as B A是是B的几倍的几倍.五、引导非限制性定语从句五、引导非限制性定语从句1.As you know,Ive decided to leave at the end of the month.2.This is also part of your work,as I told you before.3.Taiwan is,as you know,an inseparable part of Ch

10、ina.as everybody knows,as you may remember,as you say,as I can see,as I have said,as you may have heard 一些固定词组一些固定词组.六、六、as it is/as it is1、As it is,things are getting better and better.2.Leave it as it is.3.I like the house better as it is.4.State the facts as they are.用在句首的用在句首的as it is(was)与用在句末的

11、与用在句末的as it is(was)，无论在语义或用法上都是不同的，用在句首的无论在语义或用法上都是不同的，用在句首的as it is(was)前面一般要有一个与事实相反的情节，而用前面一般要有一个与事实相反的情节，而用as it is(was)来陈述真实的情况，通常译为来陈述真实的情况，通常译为“事实上事实上”“实际上实际上”“实际情况是实际情况是”。句末则表示。句末则表示“按原来的样按原来的样子子”“照现在的样子照现在的样子”，常放在名词或代词的后面，常放在名词或代词的后面，it替代前面的单数名词，是复数则有用替代前面的单数名词，是复数则有用as they are。（事实上）（事实上）（

12、别动它，保持原来的样子）（别动它，保持原来的样子）（现在的样子）（现在的样子）（实事求是地把事实摆出来。）（实事求是地把事实摆出来。）as固定词组固定词组1.as/so far as2.as long as/as long as3.as much/many as+数量词数量词4.as much as/as high as(反义词反义词as little as)5.as tall as6.as well/as well as7.as for/as to8.as if/as though在在范围内，到范围内，到程度；一直到程度；一直到；像；像那么远那么远只要；与只要；与一样远一样远也，又；与也，又；与一样好一样好言其多言其多与与一样高一样高至少；关于至少；关于好像，似乎好像，似乎