The train _____ she was traveling was late.a where b in that c on which d which明显答案是c,不过我想问,a where 为何不能选,where 不是等同 on which么

问题描述:

The train _____ she was traveling was late.a where b in that c on which d which
明显答案是c,不过我想问,a where 为何不能选,where 不是等同 on which么