The task appears to be transforming direct questions into indirect statements. Here are the answers based on the given sentences:

7. We're not sure "where we should hang the painting."
→ We're not sure where we should hang the painting.

8. He wondered "how he could tell this news to his parents."
→ He wondered how he could tell this news to his parents.

9. They can't decide "who should go first."
→ They can't decide who should go first.

10. 'Should I tell my parents what I really think?' she wondered.
→ She wondered if she should tell her parents what she really thinks.

11. I don't really know what I should say in my graduation speech. Can you help me?
→ I don't really know what I should say in my graduation speech. Can you help me?

12. They can't decide what they should do in this situation.
→ They can't decide what they should do in this situation.

13. She was not sure who she should contact.
→ She was not sure who she should contact.

14. 'How should we use this support service?' they wondered.
→ They wondered how they should use this support service.

15. 'Who should I turn to for help?' he asked.
→ He asked who he should turn to for help.

16. 'Mum, when should I turn off the oven?' Mai asked her mother.
→ Mai asked her mother when she should turn off the oven.

17. 'Where should we park our bikes?' asked Phong and Minh.
→ Phong and Minh asked where they should park their bikes.

18. 'Should we call her now?' he asked.
→ He asked if they should call her now.

19. 'What should we do to make Linh feel happier?' they wondered.
→ They wondered what they should do to make Linh feel happier.