is known to us all is that China has launched Shenzhou V spaceship successfully.A. ThatB

问题补充：

is known to us all is that China has launched Shenzhou V spaceship successfully.

A. That

B. What

C. It

D. As

答案：

A. That

(答案→)B. What

C. It

D. As

解析：此题考查主语从句，其主语从句缺少主语，What在此等于the thing which，故选B项。