1. Letters are typed by Mary in the office.

2. You will be helped by his father tomorrow.

3. Human life has completely changed by science and technology.

4. This bottle was broken by Peter.

5. English is being learnt in the room.

6. My mind can't be changed.

7. I hadn't been told about it.

8. Her telephone number isn’t known.

9. The children will be brought home by my students.

10. I was sent a present last week.

11. We were given more information.

12. All the workers of the plan were being instructed by the chief engineer.

13. Tea can’t be made with cold water.

14. Some of my books have been taken away.

15. The meeting will be held before May Day.

16. The engine of the car has to be repaired.

17. The window was broken and some pictures were taken away by the boys.

18. A lot of money is spent on advertising every day.