Here are the rewritten sentences:

8. "Who should I call for help?" she asked.
⇒ She had no idea **who to call for help**.

9. Mai could have good marks. She studied hard for the exam.
⇒ Mai studied hard for the exam **so that** she could have good marks.

10. Do you know the locations to buy traditional handicrafts?
⇒ Do you know **where to buy** traditional handicrafts?

11. The local weavers typically hand down their weaving techniques to their eldest daughters.
⇒ The local weavers have a tradition **of passing down** their weaving techniques to their eldest daughters.