As 的用法汇总
一 as 作连词：
1,As adj/adv as.... (第一个as 是副词，第二个是连词） 和....一样
The 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 . 你的钢笔和我的一样好写。
否定： not as/so ...as... 不如.... ....
The dictionary is not as/so useful as you think. 这本字典不如你想的那么好用。
修饰成分twice/three times/half/a quarter 等，置于as 之前：
Your bag is twice as expensive as mine. 你的包贵我的两倍。
其他结构：
As soon as .... 一....就....
As... as possible /sb can 尽可能.....
As long as.....(=so long as ....) 只要......
as well as.... (连接两个并列成分，强调的是第一项内容，第二项只是顺便提及；因此主谓一致要看第一项） ...也...; 还...ww
as far as I know 据我所知
as far as I am concerned 就我而言
2.As 时间状语从句 当.... 的时候
As/when/while 都可以接时间状语从句，表示“当... 时候”；但用as 时，则比较强调某个动作（意为在做某个动作时）的发生。
He hurt his foot as he got off the bus.他在下车的时候弄伤了他的脚。
You will grow wiser as you grow older. 你会随着年龄的增长而变得更加聪明。
3.As 原因状语从句 因为.....
As/because/since 都可以表示因果关系，连接原因状语从句；其中，because 语气最强，表示的是必然的因果关系；as 一般用于句首，语气较弱（表示解释），比较口语化；since 常用于书面语，表示对方已知的或稍加分析可知的原因 ，有“既然....”的意思。
As rain has fallen ,the air is cooler. 因为刚下过雨，空气比较凉爽。
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 believe you . 既然你对此那么有把握，他会相信你的。
4.As 让步状语从句 虽然....; 尽管.....
As 与 though /although /however (no matter how) 等都可以引导让步状语从句，区别是：
Although 的语气较为正式，可用在句首也可用于句中，though 可以用在句末(不能和but 连用，但可以用yet );
As所表示的语气较强，引导的从句要用倒装句式；however 后面可接adj/adv ,也要使用倒装句式：
Although he is quite old,he still jogs every day. 虽然他很老了，但是他每天都慢跑。
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，但却没有人受伤。
However hard he may try,he will no attain his goal. 无论他怎样努力，也达不到目标。
5.As (if/though) 方式状语从句 如同.... ;按照.....;仿佛；似乎；好像....
You should do it as I told you . 你应该按照我说的做。
He looked as if /though he was ill . 他看起来好像生病了。
It seems as if /though it is going to rain. 好像马上要下雨了。
I remember the whole thing as if /though it happened yesterday. 我记得整个事情，就像发生在昨天。
The child talked to us as if /tough he were a grownup. 那个孩子仿佛是大人一样和我们说话。
二 as 用作关系代词，引导定语从句 （用法比that 和which 较为复杂）
1.The same .... as ....
This is the same book as I read last week. 这本书和我上一周读的同样。
2 such .... as....
I don’t like such books as he he recommended . 我不喜欢他推荐的书。
3 so adj a/an n(单数） as....
I am not so strong a man as I was. 我不再和以前一样强壮。
4 as 单独引导定语从句
She is late ,as is often the case. (先行词是整个主句） 她迟到了， 这是经常的事。
To shut your eyes to the facts ,as many of you do,is foolish.
(先行词是动词不定式） 对事实视而不见，你们好多人都是这样的愚蠢。
三 as 用作介词 （作为...;以.... 身份）
1 As a student I should study hard every day . 作为学生我应当每天都努力学习。
2 He works as a waiter in the restaurant. 他在这个餐馆做服务员。
3 He came to China as a tourist five years ago. 五年前他作为游客来过中国。
4 as for..... 至于....
As for homework you can do all the exercises in the workbook.
至于作业，你们可以做完练习册里所有的习题。
四 as 用作副词 （=to the same degree or amount; equally） 同样....
They don’t have ab many airplanes. 他们没有同样多的飞机。
五 其他结构：
1 as well (也...)
For breakfast ,she has bread and milk ,and I have them as well.
早餐她吃面包和牛奶，我也是。
My grandpa likes doing kungfu ,my grandma likes it as well.
我爷爷喜欢练功夫，我奶奶也是。
2 such as... 诸如... ; 和... 一样的....
There are few poets such as Keats and Shelly .像济慈和雪莱这样的诗人现在很少了 。
Don’t do anything silly such as marry him . 不要做什么蠢事，比如去嫁给他。
They planted many flowers ,such as roses,sunflowers ,etc.他们种了许多花，如玫瑰花、向日葵等。
