when 用法I was watching (watch) TV when Shenzhou6 was sent up

when 用法
I was watching (watch) TV when Shenzhou6 was sent up into space.
when 引导的时间状语从句,从句是一般过去时,主句是过去进行时.(明白)
We heard (hear) him singing in the next room when we passed.
Mother told (tell) me not to open the door when she was away.
这两道题实在不懂紧急求助?
希望高手给解答一下.急急急急急!