Books in a library are put in a certain order to help people to find ___they want.
问题描述：
Books in a library are put in a certain order to help people to find ___they want.
A out Bthat C which D what为什么选D不选C呢
答
find what they want 的意思是找到他们所需要的(书)
这里what 引导的是宾语从句,which只能引导定语从句,修饰它前面的名词,引导词.
它是不能描述find这个动词.