This is the reason why/that she was late for school.两句话有什么区别
问题描述：
This is the reason why/that she was late for school.两句话有什么区别
答
填why
这一句是定语从句
the reason是先行词
而从句she waslate for school非常完整.
所以用关系副词why
补充：若从句结构不完整,则用关系代词which或that
例如：The reason that/which he talked about is good.