问下,That is the day( )I'll never forget ,为什么是which,修饰day为什么不是

问下,That is the day( )I'll never forget ,为什么是which,修饰day为什么不是 that is the day ( ) I'll never forget.A.which B.on which c.i September 18,1931 is the day that we'll never forget.为什么用tha 5.That is the day ______I'll never forget.\x0bA.which B.on w I'll never forget the day when/which .什么情况下用when,什么情况下用which I'll never forget the day ------ he ------. I'll never forget the day on which\when I joined the party.解 I'll never forget the day on which I worked with you. I'll never forget the day which my brother joined the army. I‘ll never forget the day which he cloose什么意思 it is a place that i will never forget.为什么不是用in which. 问一个英语问题哈!I'll never forget the day ( ) we stayed in the coun