Ответ:
1. He was driving a car when he reached the airport.
2. We had pack already packed all our bags when they phoned us.
3. It was snowing and no plane was able to take off.
4. Our guide had organized our trip before we talked to him.
5. She washed up after her mother came home.
6. They had been looking / had looked forward to this holiday before they managed to find it.
7. Mark had already been to Africa twice before he got married.
8. We had booked our flights weeks before we left .
9. The scientist were preparing the article at 5 o’clock yesterday.
10. I had cooked breakfast by 5 o’clock.
Объяснение: