1. We sent for the doctor. The doctor was sent for.
2. People often lie about me. I am often lied about.
3. They don't pay nurses enough. Nurses aren't paid enough.
4. Someone is painting the walls. The walls are being painted.
5.They will build a shopping center in May. A shopping center will be built in May.
6. Is someone helping you, sir? Are you being helped, sir?