as as引导的定语从句和比较状语从句有什么区别

Question

如题所述

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。