问题补充：
Willpower is a kind of quality, is it takes to do anything well.
A. what; which
B. what ;what
C. which; which
D. which; what
答案：
A. what; which
B. what ;what
C. which; which
(答案→)D. which; what
解析：考查定语从句及名词性从句。which引导非限定性定语从句，what引导表语从句，在从句中作宾语，选D。
