Giúp mình với ạ help me

1. Letters are typed in the office by Mary.

2. You will be helped by his father tomorrow.

3. This bottle  was broken by Peter.

4. English is being learnt in the room.

5. My mind can be changed by nothing.

6. Her telephone number isn't known .

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

8. I was sent a present last week.

9. We were given more information.

10. Tea can't be made with cold water.