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

题目

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

答案

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”.