Viết lại câu không đổi nghĩa

1. David had gone home before we arrived. -> After ………………………
2.  We had lunch then we took a look around the shops. -> Before ………………
3. The light had gone out before we got out of the office. => When…………………….
4. After she had explained everything clearly, we started our work. -> By the time …….
5. My father had watered all the plants in the garden by the time my mother came home.
- Before …………………………………………………………….