Ответ:
1-ое задание:
1. was
2. were
3. was
4. was
5. was
6. were
7. were
8. were
9. was
10. were
11. was
12. were
13. was
14. were
15. were
16. was
17. was
18. were
2-ое задание:
1. were
2. were
3. was
4. were
5. wasn't / was
6. were / weren't
7. were
8. was
3-е задание:
1. Bob was at school 2 days ago.
2. The children were in the park last Saturday.
3. Kate and Mary were in the zoo yesterday.
4. My friend was in the café.
5. My father wasn't at work. He was sick last week.
Good luck!