1.David had gone home before we arrived 
=> After David had gone home, we arrived.
2. We had lunch then we took a around the shops 
=> Befove we took a around the shops, we had had lunch. 
3. The light hat gone out befove we go out of the office 
=> When we got out of the office, the light hat gone out.
4. After she had explaned everything clearly, we stared out work 
=> By the time we stared out work, she had explain everything clearly.

1. After David had gone home, we arrived.

2. Before we had lunch , we took a look around the shops.

3. When we got out of the office, The light had gone out.

4. By the time we started our work, she had explained everything dearly.

5. Before my mother came home, my father had watered all the plants in the garden.