We have several subjects,and I think ( )English is the easiest to follow.为什么填of them?

题目

We have several subjects,and I think ( )English is the easiest to follow.为什么填of them?
为什么不用of which呢?

答案

因为句子中已经有了连词and,所以不能再用of which这样的从句结构.
句子有以下几种基本结构：
1.用连词连接的两个分句
2.主从句
3.";"隔开的两个分句