As的用法小结.docx

As的用法小结
as可以作连词、介词及关系代词和副词。现将其用法小结如下 ：
（一） 、as作连词的用法：
作 在 期间，当----的时候"、while的用法区别。
下列情形时，只用as,而不用when或while。
1） 用于表示同一个人的两种动作交替进行 ，指一边----：
The girl sings as she goes to school.
He looked behind occasionally as he went forward in the forest.
2） 表示两个同步发生的动作或行为 ，意思是随着-----：
As time went on / by, she became more and more beautiful .
As children get older, they become more and more interested in everything.
3） 表示两个短暂行为或事情几乎同时发生 .如:I watched her as she read the book.
I thought of it just as you opened your mouth.
Just as the flying worm hit her face, she gave a loud cry.
4） 接在名词后面表示某一个年龄段时 .如：
As a young man, he was active in sports.
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 I was at college, I could speak
several foreign languages. When the clock struck twelve, I had slept for 2hours.
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.
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
he' s been ill for ages, I will hel p him.
As / Since you're not feeling well, you may stay at home.
As he wasn't ready , we went without him.
As =in the way that 作”像”、”按照 的方式"解,引导方式状语从句。如:
Do as I told you.
Remember, you must do everything as I do.
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 as much as possible.
I don't speak English so/ as well as she does.
表示虽然，尽管 等，引导让步状语从句，常用倒装语序，模式为：
adj. /adv. / n.+as + 主语 +谓语 + 主句。如:Young as he is, he knows much.
Tired as they were, they walked on.
表示也 一样。 She is a doctor, as was her husband.
（二） 、as作关系代词，引导定语从句，表示正如，：
He is very careful, as we all know.
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 girl as she can learn anything quickly.
I was reading the same book as he bought yesterday.
（三） 、as作介词的用法.
表示好像。如 :He dressed as a policeman.
表示作为当作。如： I found a job as a guide.
当某人是某身份时。如： As a child , she was sent to abroad.
as引导的介词短语大多用作状