一，副词adv：
1. 跟...一样地,同样地 例如:I'm as tall as him 我和他一样高。
2. 如同;例如 例如:There are lots of famous buildings as the Eiffel Tower and the Arch of Triumph. 这里有许多著名建筑如埃菲尔铁塔和凯旋门。
二，介词prep：
1. 作为,以...的身份 例如:He works as a tour guide. 他作为导游工作。
2. 当作 例如:She is a famous person as a actress. 作为一个女演员,她很出名
3. 像;如同 例如:The old woman was dressed as a young lady. 这位老妇人打扮得像一位年轻人。
三，连接词conj：
1. 像...一样；依照；像 例如:You ought to do as Paul tells you. 你应按照保罗吩咐的做。
2. 当...时 例如:As she was leaving the room she remembered that book. 她离开房间时想起了那本书。
3. 随着 例如:As the sun rose the fog dispersed. 太阳一出来,雾随之消失。
4. 因为 例如:We didn't know what to do as we were just visiting there. 我们不知道该怎么办，因为当时我们仅仅在那里作访问。
5. 虽然 例如:Tired as he was, he stayed up late. 他虽然疲倦，可仍然很晚才睡。
6.尽管 例如：Try as she might,Sue couldn't get the door open.尽管想尽一切办法，苏还是不能打开那扇门
四，代词pron:
1. (与such,the same,as等连用,引导关系从句)与...相同的事物(或人) 例如:He has
earned as much money as I have. 他赚的钱和我赚的一样多。
2. (引导从句,对前述内容作补充)本情况,该事实 例如:She has married again, as was expected. 她已再婚,这是意料中的事。
四、英语中as……as的用法:
(1) 在否定句中，第一个 as 也可换成 so。
(2) 在该结构的两个as之间通常接形容词或副词的原级，但若涉及数量或程度，可用“as much 不可数名词 as”和“as many 复数名词 as”。
I haven’t got as much money as I thought. 我不像原来想像的有那么多钱。
(3) 第二个as后接从句时，该as通常为连词，但有时这个as还充当其后从句的主语或宾语，此时该as实为关系代词。如：
I gave him as much as he could eat. 他能吃多少，我就给了他多少。
(4) 该结构根据情况可用使用以下修饰语。如：(not) nearly, almost, just, nothing like, exactly, not quite, half, one-ten, twice, three times, 30 per cent等，并且这些修饰语必须置于第一个as之前，而不能置于其后。
注意：
一、 as作连词的用法:
1. 作"当……的时候",引导时间状语从句。注意与when、 while的用法区别。
① when作"当……的时候"解,可以指较短的(一点)时间,也可指一段时间。如:
When he was at college, he could speak several foreign languages.
When the clock struck twelve, all the lights in the street went out.
② while常表示一段较长的时间或一个过程,强调主句谓语动词与从句谓语动词同时发生。如:
Work while you work. Play while you play. 工作的时候工作。玩的时候玩。
③ 但属下列情形时,只用as, 而不用when或while。
A) 用于表示同一个人的两种动作交替进行,指"一边……,一边……"。如:
The girl dances as she sings on the stage.
He looked behind from time to time as he went forward.
B)表示两个同步发展的动作或行为,译为"随着……"。如:
As time went on / by, she became more and more worried.
As children get older, they become more and more interested in the things around them.
C)表示两个短促行为或事件几乎同时发生。如:
I thought of it just as you opened your mouth.
Just as the flying worm hit her face, she gave a loud cry.
D) 后接名词表示某一年龄段时,用as。如:
As a young man, he was active in sports.
2. as=since, 作"既然"、"由于"解,引导原因状语从句,常用来表示已为人们所知或显而易见的原因或理由。如:
As / Since you're not feeling well, you may stay at home.
As he wasn't ready in time, we went without him.
3. as=in the way that, 作"像"、"按照……的方式"解,引导方式状语从句。如:
He speaks English as Americans do.
Remember, you must do everything as I do.
4. 用于as...as...或not so/ as...as...中,前一个as是副词,后一个as是连词,引导比较状语从句。如:
They helped the old man as often as possible.
I don't speak English so/ as well as he does.
5. 作"虽然"、"尽管"解,引导让步状语从句。常用倒装语序,即adj. /adv. / n. as 主语 谓语 主句。如:
Tired as they were, they walked on.
Child as he is, he knows a lot. (child前不用冠词)
二、 as作关系代词,引导定语从句,作"正如"、"这一点"解。如:
He is very careful, as his work shows.
As is well-known, Taiwan belongs to China.
另外,当先行词被the same, such等词修饰时,常用as来引导定语从句。如:
Such a clever boy as he can learn anything quickly.
I was reading the same book as he bought yesterday.
三、 as作介词的用法:
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 League member, I'll take the lead in everything. (状语)
She works as a doctor. (状语)
They have me as one of their own children.(引起宾语补足语)
短语
as well 也；同样地；还不如
as well as 也；和…一样；不但…而且
as one 一致的
