is known to all, persistence is a kind of quality and that’s it takes to do anything well.
A. As; which
B. It; which
C. It; what
D. As; what
网友回答
A. As; which
B. It; which
C. It; what
(答案→)D. As; what
解析：句意：众所周知，坚持不懈是一种品质，是我们做任何事都需要的品质。as is known to all, 众所周知，相当于 It is known to all that.... what引导表语从句，做take的逻辑宾语。which在从句中的意思是哪一个。由句意可知选D。
考点: 考查代词的用法。