Ответ:
1. When Sara arrived at the party, Paul had gone home.
2. The teacher had explained the task by the time i arrived.
3. The show had finished by the time i arrived.
4. The cat killed the mouse after she had played with it for some time.
5. Peter passed the driving test because he had practiced a lot for it.
6. I stayed at home last night because dad had promised to play chess with me.
7. I had finished eating dinner when you called yesterday.
8. My favourite television program had finished before i turned the TV on.
9. I had completed the test before i realized that i was in the wrong class.
10. The house was dirty - they hadn't cleaned it for weeks.