----------,work songs often exhibit the song culture of a people in a fundamental form.

问题描述:

----------,work songs often exhibit the song culture of a people in a fundamental form.
A They occur where they are B Occurring where
C Where they occur D Where do they occur 选C,句子怎么理解啊,还有句子结构怎么分析啊?

意思是:在它产生的地方,劳动号子通常以原始的形式展示出这个民族的歌唱文化.where they occur应该作地点状语.