Ответ:
1. Jill had phoned Dad at work before she left for her trip.
2. Susan turned on the radio after she had washed the dishes.
3. When she arrived the match had already started.
4. After the man had come home he fed the cat.
5. Before he sang a song he had played the guitar.
6. She watched a video after the children had gone to bed.
7. After Eric had made breakfast he phoned his friend.
8. I was very tired because I had studied too much.
9. They had ridden their bikes before they met their friends.
10. After we had eaten the cornflakes, Henry came in.
11. Before Ken ran to Kerry's house, he had phoned him.
12. After they had packed their rucksacks, they rode away on their bikes.
13. Gerry helped his grandma in the house because his father had told him so.
14. The cat hid under the chair because the children had been so loud.
15. Before the students started to write, the teacher had collected their mobile phones.
16. After Max had finished his breakfast, he left the flat.
17. Laura repaired her glasses because her brother had broken them.
18. By the time the show began, all friends had arrived.
Объяснение: