Chuyển các câu sau sang thể bị động: Why didn't they help him? How long have they waited for the doctor? What time can the boys hand in their papers?

Chuyển các câu sau sang thể bị động:
1. Why didn't they help him?
2. How long have they waited for the doctor?
3. What time can the boys hand in their papers?
4. Where do people speak English?
5. How did the police find the lost man?