Here are the correct answers for the items in the first part of the exercise:

1. A (at)
2. A (was riding)
3. A (any)
4. B (hers)
5. A (somebody)
6. C (plays)
7. A (didn’t see)
8. C (went)
9. A (10)
10. A (at)
11. B (his)
12. A (anybody)
13. A (does)
14. B (bought)
15. A (went)
16. A (much)
17. C (is doing)
18. A (this)
19. A (is)

For the second part of the exercise, fill in the gaps with "shall," "will," or the correct form of "be going to":

1. Shall ... I cook something for dinner?
2. Let’s go out instead.
3. That’s a good idea! I will phone Chris and ask him to come too.
4. Don’t bother. He’s got other plans. He is going to have dinner with his grandparents.
5. Oh! OK, then. Shall I call the restaurant and book a table?
6. That would be great. Thanks!

If you have any specific questions or need further assistance, feel free to ask!