一)as作副词,表示程度,意为“同样地”。在“as...as...”,“not as...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 as you.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 ran along.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 play piano.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 to do.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 the south.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 is true.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 the difficulties.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”,“the same...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 Feng was.他曾希望做一个像雷锋那样的人。

My hometown is no longer the same as it was.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 the earth.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 to you.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 make progress.只要你努力,你就会取得进步。

3.as if/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 her own.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“It appears/looks/seems...+as if/though”句型结构中。eg;

It appears as if/though it is going to clear up.看起来天要晴了。

It seems as if/though he knew nothing about it.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/many as作“多达...”,“达到...之多”解。eg:

He can earn as much as 5000 dollars a month.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 next Monday.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 the accident.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 as well.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 the exam.他努力学习以便通过考试。(