my father was watering the plants when I got home.(对划线部分提问)

问题描述:

my father was watering the plants when I got home.(对划线部分提问)
watering the plants 这是下划线部分.
______ ______ your father ______ when you got home

watering the plants是他正在干的事,对此提问就是
what was your father doing when you got home.
我到家的时候爸爸在浇植物
你到家的时候你爸爸在干吗?