1. Mary types letters in the office. 

⇒ Letters are typed in the office by Mary

2. His father will help you tomorrow. 

⇒ You'll be helped by his father tomorrow.

3. Science and technology have completely changed human life.

⇒ The human life has completely been changed with science and technology.

4. Peter broke this bottle.

⇒ This bottle was broken by Peter 

5. They are learning English in the room.

⇒ English is being learnt in the room.

6. Nothing can change my mind.

⇒ My mind can't be changed

7. No one had told me about it.

⇒ I hadn't been told about it.

8. I don’t know her telephone number

⇒ Her telephone number isn't know

9. My students will bring the children home.

⇒ The children will be brought home by my students.

10. They sent me a present last week.

⇒ I was sent a present last week.

HỌC TỐT!