1/ After David had gone home, we arrived.
2/ Before we took a look around the shop, we had lunch.
3/ When we got out of the offcie, the light had gone out.
4/ By the time she had explained everything early, we started our work.
5/ Before my mother came home, my father had watered all the plants in the garden.
6/ By the time he going to work this morning, he hadn't locked the door.
7/ After these students had taken an exam, they had a summer holiday last year.