as和 which在特殊定语从句中作补语.如：We thought him a gentleman,as/which h

首先说明一下,我只是谈一下个人理解,大家交流一下,不知能否解决你的疑惑.

"如果先行成分不是主语补语或宾语补语,关系代词用which而不用as.如： He talked like a native, which/as he hardly was. "貌似有点问题,不大懂你的意思.

which可以在特殊定语从句中作定语,修饰fact, matter, thing 等名词.这些名词代表先行成分表达的意义,有时将其略去句义仍然完整.as不能作定语.如： I was told to go not by train but bus, which advice I followed.这里就理解成为同位语从句就好了,同位语从句大部分就是抽象名词+that的形式

as”特殊定语从句中可以主谓倒装,这个现象好像没听说过.大部分好像都是状语从句.
eg：As he is a child ,we shouldn't scold for him.
倒装成：child as he is ,we shouldn't scold for him.

As做成分的,如Taiwan is, as you know, an inseparable of China.(as是关系代词,成分可以看作宾语）这里的“as you know" 理解为插入语就好了.
as you know (Taiwan is an inseparable of China) 主要是用来修饰括号里的宾语从句.不需要理解他到底做不做成分.
就像我们常说： As is known to all ,. as很明显做的事主语从句,可我们也很少去纠结他.
as we know,.这里的as就可当while,when理解.当我们知道,提及什么时
其实你完全就可理解为插入语,不影响句子任何成分.

that引导定于从句若作主语是不能省略的.这是肯定的.应为that 引导定语从句时,他代替的是前面的先行词,先行词在从句肯定是做成分的,只有that引导宾语从句时才能省略.


She knew a little corner（ 为什么不是that.不太明白where请详解） was the seat beneath the yew tree.that是要做成分的,而where不做成分.（个人感觉这句子有点问题,不知你从哪找的)

i had just been reading a patent liver-pill circular,in which were detailedthe various symptom
I had just been reading a patent liver-pill circular,（ 为什么是in which不太明白,请详解） were detailedthe various symptom这里的 in which =where 引导地点状语从句.
谢谢!