is well known is the Diaoyu Islands have been part of China since ancient times.A. Which

问题补充：

is well known is the Diaoyu Islands have been part of China since ancient times.

A. Which; that

B. That; which

C. What; that

D. That; what

答案：

A. Which; that

B. That; which

(答案→)C. What; that

D. That; what

解析：考察名词性从句。第一空What引导主语从句what is well known且在句中作主语。第二空that引导表语从句that the Diaoyu Islands have been part of China since ancient times.此句子结构很完整，只需要使用that引导，that在句中不充当任何成分，只起引导作用。句意：众所周知的事情是钓鱼岛自古以来就是中国的一部分。故C正确。