when () Mr White __(leave) home?sorry I don't know I __(not notice) him leaving
问题描述：
when () Mr White __(leave) home?sorry I don't know I __(not notice) him leaving
mother is going __(swim) this afternoon
答
when (did) Mr White (leave) home?
sorry I don't know I (didn't notice) him leaving
My mother is going 【to swim】 this afternoon