10.We shall never forget the days ___ we worked together.

on which D. that B,为什么不选CA. in which C. which
z这道题选B

on which
这题为什么又选D. at which B. I will never forget the day____ we studied together. at that D7.
A. on that
C

in 在这里指在一段时间内
on 一般指具体的某一天

有在那些天里面的意思。

a 定语从句中缺少时间状语，要有关系副词when在从句中充当