The last time ___ I saw him was last Friday

问题描述:

The last time ___ I saw him was last Friday
空里应该填that还是when?

when,上一次我见他的时候是上周五
主句是the last time was last friday.而i saw him发生的时间是the last time,时间装语的关系,
i saw him in the last time ,用when.