as引导定语从句
As 引导的定从
as引导的定从很多人不是很熟悉，我们下面专题讲解。
在定从中，as 是关系代词，在从句作主语或宾语。
1 限制性定从（只用在固定结构中）
(1) such +N+as….
Such inns as there were were generally dirty and flea-ridden.（as 作主语）
=There were inns and inns were generally dirty and flea-ridden.
那有一些小旅馆，旅馆通常很脏而且布满跳蚤。
Such people as are indolent are not easy to make their goals a reality.
懒惰的人不容易实现目标。
These are such points as they discussed at the meeting.
这些是他们在会上讨论的观点。
(2) as +adj +N +as +…
You should drink as much water as is required. （第二个as 作主语）
你应该尽可能多的喝被要求喝的`水。
You’d better make as few mistakes as we did.（第二个as作宾语，引导定从）
你应该尽可能少犯我们犯过的错误。
(3) the same +N +as…
He uses the same book as I bought.
他平时用的书和我之前买的那本一样。
He uses the same book that I bought.
他平时用的书就是我之前买的那本。
2 as 引导非限制性定从
要点：as引导定语从句的先行词是一句话。
例如：
As the proverb says, each coin has two sides.
=Each coin has two sides, as the proverb says.
=Each coin, as the proverb says, has two sides.
=Each coin has two sides, as the proverb says.
=Each coin has two sides, which the proverb says.
注意：as引导的非限制性定从可放在句首、句中、句末；
which引导一个句子为先行词的非限制性定从只能放在句末。
以下是固定句式：
As is often pointed out, sth is a two-edged weapon which can be used equally for good or evil.
正如经常指出的，...是一把双刃剑，既可以用于造富，也可以用于为害。
As is depicted in the figure,the pork price has been rising.
As we can see in thefigure, the pork price has been rising.
常用写作句式:
As is obviously betrayed in the figure/chart, …
As is vividly depicted in the cartoon, …
As we can see in the picture, …
As 引导定从与状从的区别
As 是否在从句中做成分
As he says,Tom is wearing two hats.
（定语从句）
As he says it, Tom is wearing two hats.
（状语从句，as 不做成份，只起连接作用，it指的是整个句子：Tom is wearing two hats.)
