Здесь нужно сверху, над глагольными формами, указать последовательность событий с цифр 1 и 2 (1 - что случилось раньше, 2 - что произошло потом).
2 1
1. By the time I left the building everyone had gone home. (то есть, сначала все ушли, потом я)
2 1
2. I looked in the garden, but they had already gone to work.
1 2
3. They had cleaned everything up by the time their parents returned.
1 2
4. I had already taken three aspirins, but they didn't help.
2 1
5. I wanted to have a bath, but someone had used all the hot water.
1 2
6. We had made our plans carefully and won the prize.
1.lived 2.was cutting 3.heared 4.wondered 5. had happened 6.went 7. to look 8.saw 9. was built 10. prepared 11. to kill 12.defended 13. stroke 14.found 15. killed 16.set 17. was walking 18.fell 19.saw 20.went 21.came 22.was built 23.was surprised 24. didn't expect 25. knocked 26. came