Упражнение 1 (Подробнее расписаны те предложения, где меняется порядок слов; всё, что не написано, остаётся так, как в задании).
1. played
2. was playing
3. What was Nick doing…
4. What were you doing when…
5. wasn't sleeping
6. What did he do…, read
7. Was she sleeping when…
8. didn't play, played
9. wasn't playing
10. was cooking
11. washed
12. Did you do your…

Упражнение 2.

1. went
2. was going
3. was doing
4. didn't play, wrote
5. wasn't sleeping, was doing
6. went, found, brang, decided, fed, took
7. was going, were talking and laughing

Упражнение 3.

1. came, was sleeping
2. came, was playing
3. came, were plaing
4. came, was wathing
5. opened, was sitting
6. was crossing, fell
7. was going, met
8. was going, saw