is known to us all that the Olympic Games will take place in LondonA. ItB. WhichC.

问题补充：

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

A. It

B. Which

C. As

D. What

答案：

(答案→)A. It

B. Which

C. As

D. What

解析：考查：it 做形式主语，真正的主语是that后的从句。句意：奥运会在伦敦举行我们都知道。故选A。