如 the time 在定从中做主语、宾语时，用 which ，如： During the time which is unforgetable（在令 …
We use during before nouns and noun phrases to refer to when something happens over a …
一、 during which的用法. during which 相当于 during the time / the period / the course of …
更多内容请点击：during a time后面加when还是which？ - 知乎 推荐文章