..is known to everybidy,the moon travels round the earth once every month

题目

..is known to everybidy,the moon travels round the earth once every month
a.it
b.as
c.that
d.what
为什么?

答案

B
As is known to ...做状语是一个固定用法 记住就行了,从语法上解释比较麻烦
如果后面有that的话,就用it's known to..构成强调句