题目内容：

As is know to all的句型为什么不能是As it is know to all

优质解答

是known.
as is known to all,这里的as指代的是后面所说的东西,作代词
as it is known to all,这里as是连词,连接一个完整的句子,是“因为”的意思,这样就是“因为这个已经众所周知”.