is known to us all is that the Olympic Games will take place in London.A. AsB. WhatC

问题补充：

is known to us all is that the Olympic Games will take place in London.

A. As

B. What

C. That

D. It

答案：

A. As

(答案→)B. What

C. That

D. It

解析：考查名词性从句。句中what引导主语从句，在从句中作主语，故选B。