of whom和of them的区别,most of whom和most of them的区别

china has many famous writers ,one of whom is lu xun 只有一个句子,句子又有主语,one of whom 是从句的主语
china has many famous writers and one of them is lu xun 有连词或者是多个句子,
of them和most of them只是意思上的区别,most of whom和most of them的区别与of whom和of them的区别一样