When I try to find that prevents so many people from taking part in the program,it seems to me that there are two main causes.
A. why it does
B. what it does
C. what it is
D. why it is
网友回答
A. why it does
B. what it does
(答案→)C. what it is
D. why it is
解析：find后为一个宾语从句，而且这个从句为强调结构。全句的意思是“当我想努力找出阻止许多人参加这一节目是什么原因时，依我看似乎有两个理由”。