It Is known to us 和as is known to us 有什么区别
1、It Is known to us that /to do是独立句，其中it 是形式主语，真正主语是后面that 从句或to do动词不定式，举例如下；
It Is known to us that the earth revolves around the sun.
众所周知，地球围绕太阳公转。
2、as is known to us 是从句，非限定定语从句前置形成，举例如下；
the earth revolves around the sun，which Is known to us.
地球围绕太阳公转，这个我们都知道。
当非限定定语从句which Is known to us前置到句首，which必须换成as，转换成as is known to us，所以形成；
as is known to us， the earth revolves around the sun.
3、as is known to us不能作为独立句，后面必须接主句；
As is known to us, the chinese are a industrious and gallant nation.
众所周知，中国人民是勤劳勇敢的民族。
1、It Is known to us that /to do是独立句，其中it 是形式主语，真正主语是后面that 从句或to do动词不定式，举例如下；
It Is known to us that the earth revolves around the sun.
众所周知，地球围绕太阳公转。
2、as is known to us 是从句，非限定定语从句前置形成，举例如下；
the earth revolves around the sun，which Is known to us.
地球围绕太阳公转，这个我们都知道。
当非限定定语从句which Is known to us前置到句首，which必须换成as，转换成as is known to us，所以形成；as is known to us， the earth revolves around the sun.
3、as is known to us不能作为独立句，后面必须接主句；
As is known to us, the chinese are a industrious and gallant nation.
众所周知，中国人民是勤劳勇敢的民族。
1，It is known to us all中的It为形式宾语,因此这种结构后必须接一个主语从句来作真正的主语.
这个主语从句可以是that或wh-类连词引导的从句.即:
It is known to us all+that/what/when/where/how从句.
2，as is known to us all是由as引导的定语从句,
as指代后面或前面的整个主句,因此as is known to us all结构可放句首,也可放句中或句末,
但一定要用逗号与主句隔开.
3，what is known to us all是一个名词性从句,常用来作主语从句,用于这个结构中:
What is known to us all is that....
例如:
It is known to us all that he will visit our school tomorrow .
=As is known to us all , he will visit our school tomorrow .
=What is known to us all is that he will visit our school tomorrow .
As is known to us all, the earth goes round the sun!
=It is known to us all that the earth goes round the sun!
=What is known to us all is that the earth goes round the sun!
It is known to us all when the meeting will be held .
=It is known to us all where the meeting will be held .
=It is known to us all why you didn't come to school yesterday.
而it is known to all 是形式主语的典型,只用于如it is known to all that our teacher is beauful.
精——锐
it is known to us that+句子
as is known to us, 后面是逗号 固定用法
what is known to us is that+句子
