Помогите пожалуйста.

Future Indefinite or Future in the Past

5. I (go) to the post-office for you?
6. I had no idea when they (come).
7. We said we (not watch) TV all day long.
8. I doubted if they (make) it up.
9. Tell them again, perhaps they (understand).
10. They (come) if we invite them?
11. There (be) a lot of people at the conference.
12. She says she (have to) change the clock.
13. She was afraid he (feel) depressed.
14. I assure you he never (tell a lie).
15. They say this firm (publish) this book next year.