Answer:
1. An, A
2. Any, Some
3. Any, Some
4. A, A
5. Any, A
6. A, A
7. Any, Some
8. A, Some
9. A
10. An, A
11. Any, Some
12. Any
13. An
14. An
15. Some, A
16. Any
17. Some, A
18. Some
19. Any, Some
20. An
21. Any
Explanation:
I'm pretty sure these are right :)
