Question

as as引导的定语从句和比较状语从句有什么区别

Answer 1

区别就是定语从句和状语从句的最大区别
定语从句是缺少成分（逻辑上应该是先行词原本担任的成分）的，所缺的成分由相应的引导词（据先行词而定）补全
状语从句是不缺成分的，它的引导词内容意义大于语法意义（仅仅表达转折、让步等意思而无担任从句成分的语法功能），已经相当于连词
以as为例，as在引导定语从句时相当于代词，一般作主语，而引导状语从句时可是为连词，表原因、让步等等（引导让步必须前置从句成分）
试比较
As
is
known
to
all
(定语从句，as作从句主语)
,
blablabla
As
it
is
known
to
all
(状语从句，从句不缺成分，as可视为连词),
blablabla
as和which引导非限制性定语从句的区别
区别：
1）as可指其前后主句提到的事实或情况，因此引导的非限制性从句位置比较灵活，which可以放在主句前后，也可插入主句之中；而which引导的非限制性从句只能位于主句之后：
As
is
known
to
all,
fish
can’t
live
without
water.
Air,
as
we
know,
is
gas.
2）在非限制性从句中，which后的be动词不可省；as而后的be动词可以省略：
She
told
me
she
won
the
match
,
which
was
a
lie.
The
material
is
elastic,
as
(was)
shown
in
the
figure.
3）
which在非限制性定语从句做主语时可用各类动词做谓语；而在非限制性定语从句做主语时，谓语常用连系动词，如be,
seem,
become等，一般不用其他行为动词：
He
saw
the
girl,
which
delighted
him.
He
didn’t
say
anything
at
the
meeting
,
as/which
seemed
very
strange.
as引导的让步状语从句有几种模式
as可引导让步状语从句，表示“虽然、尽管”，但要用部分倒装结构，形式如下：
1.
形容词
+
as
+
主语
+
系动词。如：
Tired
as
he
is,
he
offers
to
help
me.
尽管他已经很累了，他还是主动提出帮助我。
2.
过去分词
+
as
+
主语
+
系动词。如：
Well-written
as
the
book
is,
the
author
is
not
satisfied
and
prepared
to
revise
it.
尽管这本书写得很好，作者还是不满意并打算修改它。
3.
名词
+
as
+
主语
+
系动词。如：
Student
as
he
is,
he
does
not
study
hard.
他虽然是个学生，却不努力学习。