爱华网一）as作副词，表示程度，意为“同样地”。在“as．．．as．．．”，“notas．．．as．．．”结构中的第一个as是副词，作“和／与．．．(不)一样”解。eg：
Jack is as tall as his father．杰克和他的父亲一样高。
He doesn't speak English as／so fluently asyou．他的英语说得不如你流利。
二）as作介词。
1．作“如，像”解。eg：
They got united as one man．他们团结得像一个人一样。
2．作“充当，作为”解。eg：
As a writer，he was famous．作为作家，他是很有名的。
三）as作连词，常用来连接主句和状语从句。
1．引导时间状语从句，作“当．．．的时候”解，有“随着．．．”之意，与while意义相近，强调两个动作同时发生；或某事一发生，另一事立即发生。eg：
He shouted aloud as her ranalong．他一边往前跑，一边高声地呼喊。
I was startled as he opened the door．他一开门，我吓了一跳。
as作连词，相当于when。eg；
As a little boy (When he was a little boy)he began to learn to playpiano．他小时候就开始学弹钢琴。
2．引导原因状语从句，作“因为，由于”解，与because的用法相近。eg；
I must stop writing now，as I have rather a lot of work todo．我必须停笔了，因为我还有许多工作要做。
3．引导方式状语从句或比较状语从句，作“正如，(如)像”解。例eg：
As in your country，we grow wheat in the north and rice in thesouth．正如(像)你们国家一样，我们在北方种小麦，在南方种大米。(方式状语从句)
When at Rome，do as Romans do．入乡随俗。(方式状语从句)
4．引导让步状语从句，作“虽然，尽管”解。这时从句常用倒装语序，即把从句中的表语、状语或动词原形放在as之前。eg；
Strange as it may seem，it istrue．尽管这事看上去很奇怪，但却是真的。
Try as he might，Tom could not get out of thedifficulties．不管怎样努力，汤姆还是摆脱不了困境。
四）as作关系代词。
1．引导限制性定语从句，用在“such．．．as”,“thesame．．．as”，“as．．．as”等结构中，常译作“像．．．一样的人(或物)”，“凡是．．．的人(或物)”。例eg：
He wished to be such a man as Lei Fengwas．他曾希望做一个像雷锋那样的人。
My hometown is no longer the same as itwas．我的家乡再也不像过去一样了。
2．引导非限制性定语从句，用来指代它前面的整个句子(即先行句)，意思是“这一点”。这个分句可以位于句首、句中或句末。eg：
As is well known，oceans cover more than 70％ of theearth．我们知道，海洋占地球面积的百分之七十以上。
五）含as的固定词组的用法
1．as soon as作“一…就”解，引导时间状语从句。eg：
As soon as I get to Beijing，I'll write toyou．我一到北京，就给你写信。
2．as／so long as作“只要”解，eg；
As／So long as you study hard，you'll makeprogress．只要你努力，你就会取得进步。
3．asif／though常用来引导方式状语从句，作“好像，仿佛”解。如果从句中讲的是非真实情况，则用虚拟语气。eg：
She loves the child as if／though he were herown．她爱这个孩子如同爱自己的孩子。
As if／though也可用来引导表语从句，常用在“Itappears／looks／seems．．．+as if／though”句型结构中。eg；
It appears as if／though it is going to clearup．看起来天要晴了。
It seems as if／though he knew nothing aboutit.他好像对此事一无所知。
4．as to作“关于，至于”解。eg；
There is no doubt as to his honesty．他的诚实是无可置疑的。
5．as much／manyas作“多达．．．”，“达到．．．之多”解。eg：
He can earn as much as 5000 dollars amonth．他每月能挣5000美元。
6．so／as far as I know作“就我所知”解，在句中作插入语。eg：
As／So far as I know，he will come here nextMonday．据我所知，他将于下星期一到这里来。
7．as a result，as a result of表示“由于．．．的结果”。eg：
She died as a direct result of theaccident．她的死是那次事故的直接结果。
8，as well为“也，还”之意。eg：
Come early，and bring your brother aswell．早点来，把你的弟弟也带来。
9．so as to，so．．．as to若跟动词原形，表示目的或结果。eg：
He studied hard so as to pass theexam．他努力学习以便通过考试。(表示目的)as……as
AS +adj(原级)+AS
AS +adv(原级)+AS
as soon as 一……就
as soon as possible 尽可能快地
as early as possible 尽可能早的
as carefully as you can 尽可能认真地
as careful as you can 尽可能认真的
so...as 一般用于否定句,as...as一般用于肯定句,(肯定否定都能用)
so...as不可用于肯定句.as...as与so...as均可表示"与……一样",as...as...的用法:两个as中间可以加形容词或者副词,由它要修饰的内容决定.
它们的用法有异同之处:
肯定句用as...as,不用so...as;否定句两者均可使用.例如:
I didn't go as /so far as you.我走得不像你那么远.
They walked as far as the station.他们步行到了车站.
误:They walked so far as the station.
