is known to all Lu Xun was famous as a great thinker.A. Which B. AsC. ItD. What

问题补充：

is known to all, Lu Xun was famous as a great thinker.

A. Which

B. As

C. It

D. What

答案：

A. Which

(答案→)B. As

C. It

D. What

解析：考查定语从句。As is known to all，众所周知，引导非限制性定语从句，在这里指后半句的含义，句意：众所周知，鲁迅作为一位伟大的思想家而出名。所以选B。