Ответ:

1. on

2. on

3. at

4. at

5. at

6. at

7. on

8. in

9. on

10. at

11. in

12. at

13. on

14. in

15. on

16. at

17. at

18.at

19. in

Объяснение:

насчёт 1 и 17 не уверен