is known to us all is that Antarctica is the coldest place on Earth.A. ItB. AsC. WhatD. T

问题补充：

is known to us all is that Antarctica is the coldest place on Earth.

A. It

B. As

C. What

D. That

答案：

A. It

B. As

(答案→)C. What

D. That

解析：句意:大家都知道南极洲是地球上最冷的地方。这里what引导的主语从句，它在从句中做主语，that在主语从句中不作成分，it不能起引导的作用，as“正如”，根据句意故选C。