it is well-known to us that...中to us做什么成分?英语中有没有表语补足语?

it is known to us what it is ,这句话中what充当什么成分? it is well known to us that是什么意思 it is known to us It is well known to us that Zhai zhigang is the first Chines It is known to us all that email,as well as telephones,____ It is well known to us all that in china traffic the right As is known to us.和It is known to us.后面接什么啊?为啥 It's known to us that practice makes perfect.与As is known to 是what is known to us that还是what known to us is that要准确回答我们有大 ----is well known to us all that Taiwan belongs to China.--- 英语翻译As is well known to us,it is important for the students The fact that she worker hard is well known to us all .英译汉