爱华网as的用法总结
as是英语考试中用得比较多的一个词，也是很多学生反映较难掌握的一个词。as的词性较多，用法也较复杂，因此掌握该词会对英语学习很有帮助。下面笔者就对as的用法作一个简单的归纳。
一、as作为从属连词，可以引导下列从句：
1、as引导时间状语从句，意为“正当……的时候”、“一面……一面……”、“随着……”，从句可放主句之前或主句之后。
As I was coming here, I met your brother.
As he walked on, he felt himself getting more and moretired.
【知识拓展】：as与when,while都是引导时间状语从句的从属连词，含义都是"当……的时候"。但它们有区别：用when时，从句的动作可以与主句的动作同时发生，也可以先于主句的动作发生；用while时，从句的动作为一过程，主句动作与从句动作同时进行或在从句动作过程中发生；用as时，主句和从句的动作同时发生，具有延续的含义。例如：
It was snowing when he arrived at the constructionsite.他到达工地时，天正在下雪。
He was watching TV while his mother wascooking.他母亲做饭时他在看电视。
You will grow wiser as you grow older.你会随着年龄的增长而越来越聪明。
2、as引导原因状语从句，意为“由于”大多位于主句之前，偶尔在前或后。
As this question is of great importance, we will discuss it onceagain.
Water, as it occurs in nature, is never very pure.
We couldn‘t send the children to school as life was very hard inthose days.
【知识拓展】：as, because,since都可以表示因果关系，连接原因状语从句，含义是“因为，由于”，但它们有区别：because表示的语气最强；as一般放在句首，语气较弱，较口语化；since常常用在书面语中，表示多为对方已知的、或稍加分析便可得知的原因，有时可译作“既然”。例如：
He will succeed because he is in earnest.他一定会成功，因为他很认真。
Since you are so sure of it he’ll believeyou.既然你对此如此有把握，他会相信你的。
As rain has fallen, the air is cooler.因为下过雨，空气比较清爽。
3、方式状语从句，意为“如同”、“按照……的方式、样子、办法”。As从句总跟在主句之后。
You must try to hold the tool as I do. 象我那样拿住工具。
Leave things as they are. 让那些东西保持原样。
3、as引导让步状语从句，意为“虽然”，多在主句之前，且多用倒装。（应将从句主要成分的形容词、副词、原形动词、不加冠词的单数名词置于as前面）
Difficult as it is, we should not give it up.
Child as he is, he knows something about electricity.
【知识拓展】：as与although (或though)，however (或no matterhow)等都可以引导让步状语从句，含义是“虽然，尽管”，但它们有区别：although语气稍正式些，可放在句首，也可放在句中，主句中不能再用but，但可以用yet；as所表示的语气较强，引导的让步状语从句用倒装语序；however引导让步状语从句时，它的后面可跟形容词或副词，也要用倒装语序。例如：
Although he is quite old, he still jogs everyday.他虽然年纪相当大，仍然每天慢跑。
Strange as it may seem, nobody was injured in the accident.
这次意外虽然显得令人不可思议，却没有人受伤。
However hard he may try, he will not attain hisgoal.无论他怎样努力也达不到目标。
4、as引导比较状语从句，意为“和……一样/不一样”。表示同级的比较。使用时要注意第一个as为副词(意为“那么”“如此”)，第二个as为连词（引导的比较状语从句常常用省略）。其基本结构为：as+adj./ adv. +as。例如：The line AB is as long as the line CD （is）.
This film is as interesting as that one.这部电影和那部电影一样有趣。
Your pen writes as smoothly as mine.你的钢笔书写起来和我的一样流畅。
注意1：其否定式为not as/so +adj./ adv. +as。例如：
This dictionary is not as/so useful as youthink.这本字典不如你想象的那样有用。
注意2：“as…as…”结构前加上表示程度或倍数的词语作为修饰成分，如just, nearly, almost,twice, three times, half, a quarter等，则须置于第一个as之前。例如：
Your bag is twice as expensive as mine.你的袋子比我的贵一倍。
This is just as important an experiment as that（is）.
There are now three times as many schools in this city as（therewere ）ten years ago.
【知识拓展1】：几个关于as...as的常见句型：
(1)as...as possible
Please answer my question as soon as possible.请尽快回答我的问题。
(2)as...as usual/before
She looks as pretty as before.她看起来和以前一样漂亮。
(3)as long as... (引导条件状语从句)
It took us as long as three years to carry out theplan.我们花了长达三年的时间才完成这项计划。
(4)as far as
He walked as far as the railway station yesterdayevening.昨天傍晚，他一直散步到火车站。
(5)as well as
She cooks as well as her mother does.她烧菜烧得跟她母亲一样好。
【知识拓展2】：一些带有as...as结构的常见短语归纳：
as busy as abee像蜜蜂一样忙碌 as easy as ABC像ABC一样容易
as deep as awell像井一样深 as light as a feather像羽毛一样轻
as soft asbutter像黄油一样软 as rich as a Jew像犹太人一样富裕
as strong as ahorse健壮如牛as poor as a church mouse一贫如洗
as cool as a cucumber十分冷静；镇定自若
二、as作为关系代词，可以引导定语从句，既可以单独使用，也可以与其他词连用，其用法要比that和which更为复杂，而且as在定语从句中可以充当主语、宾语、介词宾语、表语，可以指人也可指物。要注意引导定语从句时。
1、引导限制性定从句。
①用于thesame...as结构中。
This is the same book as I read last week.这本书和我上周读的那本是一样的。
He isn’t the same person as he used to be.
②用于such...as结构中。
I have never heard such story as he is telling.
I don’t like such books as he recommends. 我不喜欢他推荐的那些书。
③用于"as/so +adj. + a/an + n. (单数) + as "结构中
I am not so strong a man as I was.我已经没有从前那么强壮了。
2、引导非限制性定从句，修饰整个主句或主句的一部分，可在句首、句中、句末。当 as在从句中做主语时，从句的谓语动词常是被动语态或系表结构。在从句中做宾语时，从句的谓语动词常是情态动词 + 动词原形。
As is often the case, we have overfull filled the productionplan.
This machine, as might be expected, has stopped operating.
He came very early this morning, as (was) usual.
She is late, as is often the case.她迟到了，这是经常的事。(先行词是整个主句)
To shut your eyes to facts, as many of you do, is foolish.
对事实视而不见--你们好多人都是如此的愚蠢。(先行词是不定式短语)
此外还有: as has been said before/ as may be imagined / as is wellknown/ as we all can see/ as often happens/ as has already beenpointed out等等。
三、as作为介词的用法：
1. 表示“好像”。如:He dressed as a policeman.
2. 表示“作为”，“当作”。如：I found a job as a guide.
3. 表示某人是什么某身份时。如：As a child , she was sent to abroad.
He came to China as a tourist five years ago.他五年前以游客的身份来过中国。
4. as引导的介词短语大多用作状语,as译为"作为";少数情况可引起宾语补足语。如:
As a Party member, I'll take the lead in everything. (状语)
She works as a model. (状语)
She has me as one of her best friends.(引起宾语补足语)
四、as作为副词的用法：
1、意思为“相同地”，“ 同样地”=（to the same degree or amount; equally）
例如：They don’t have as many airplanes.他们没有同样多的飞机。
This dress is twice as expensive as that one.
2、意思为“像，如”等。如：As before, he remained unmoved.
总之，通过以上的分析，我们对as的词性和用法有了比较全面的理解和把握，才能在实际的运用中做到心中有数，应付裕如。
练习:
1. ____the day went on. The weather got worse.
A. With B.Since C.While D.As
2. Mother was worried because little Alice was ill,especially____ Father was away in France.
A.asB.thatC. during D.if
3. We’d better hurry _____ it is getting dark.
A.andB.butC.as D. unless
4.____ , he doesn’t study well.
A. As he isclever B. Heis as cleverC. Clever ashe isD. As cleverhe is
5._____,I have never seen anyone who’s as capable as John.
A. As long as I havetravelledB. Now that I have travelled so much
C. Much as I havetravelledD. As have travelled so much
6.____ is mentioned above, the number of the students in senior highschools is increasing.
A. What B.AsC.ThatD.It
7.____ is known to all . China will be an___ _ andpowerful country in 20 or 30 years’ time .
A. That,advancing B. This,advanced C.As , advancedD.It, advancing
8,_ ___is known to everybody, the moon travels round the earth once everymonth.
A.ItB.asC.thatD. what
9. John plays football,if not better than, David.
A. aswell B. as wellas C. so wellD. so wellas
10. She doesn’t speak ____ her friend, but herwritten work is excellent.
A. as will asB.so often asC. so much asD.as good as
11. The horse is getting old and cannot run _____it did.
A. as fasterasB.so fast thanC.so faster asD.as fast as
12. After the new technique was introduced, the factory produced____ tractors in 1988 as the year before.
A. as twice manyB.as many twiceC.twice as manyD. twice manyas
13. With the help of the German experts, the factory produced_____ cars in 1993 as the years before.
A. as twice manyB. as many astwiceC. as twiceas many D. twice as many
14. Americans eat____vegetables per person today as they did in 1923
A. more than twiceB. as twice asmany C. twice as many asD. more thantwice as many
15. These houses are sold at such a low price _____ peopleexpected.
A. likeB. asC.thatD. which
16. It is generally believed that teaching is ______ it is ascience.
A. an art much asB.much an art asC. as an artmuch as D. asmuch an art as
17. I am at least ____ age ____ Robert if I am not older than he.
A. the same,asB. the same, withC. as same,as D. as same , with
18. The piano in the other shop will be___ __ but_____.
A. cheaper, not as betterB.more cheap, not as better
C. cheaper, not as goodD.more cheap, not as good
参考答案：1---5DACCC 6---10BCBBA 11---15DCDDB16--18DAC
