is known to us all that the sun rises in the east.A. AsB. ThatC. WhichD. It

问题补充：

is known to us all that the sun rises in the east.

A. As

B. That

C. Which

D. It

答案：

A. As

B. That

C. Which

D. It

解析：考查it做形式主语。题意 众所周知，太阳从东方升起。考查固定句型结构，it is known to sb that …某事是众所周知的。其中it 是形式主语，真正的主语是后面的that从句。

考点考查it做形式主语