Question

有关as is known to us all, it is known to us all 的辨析

1。As is known to us all, the earth is round.
2. It is known to us all that the earthe is round.
3.what is known to us all is that the whale is not fish but mammal.

请问这3个分别是什么从句啊？

Answer 1

1.As功能同于which,只是as可以放在句首。是个非限定性定语从句。
2.从句为真正主语，it为形式主语。that从句实际上是描述形式主语it的 所以还是定语从句。
3.主语从句 由what引导。

Answer 2

1.倒装
2.强调
3.主从