______ you are supposed to do ______ you don't like a thing is ______ it. Don't complain.
A.That; what; change
B.When; that; to change
C.What; when; change
D.What; that; changing
答案:C
题目分析:句意:当你不喜欢一个东西的是时候,你应该做的是改变它。不要抱怨。第一空填what连接主语从句,在主语从句中what做宾语,第二空填when,引导时间状语从句,第三空是省略to的不定式做表语,因为前面主句有do。所以选C。