1. Mary types letters in the office.
⇒ Letters are typed in the office by Mary
2. His father will help you tomorrow.
⇒ You will be helped by his father tomorrow
3. Science and technology have completely changed human life
⇒ Human life has been completely changed by 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.
⇒ It hadn't been told me
8. I don’t know her telephone number
⇒ Her telephone number isn't known
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.
⇒ A present was sent me last week

11. She gave us more information.

⇒ Wr were given more information.

12. The chief engineer was instructing all the workers of the plan.

⇒ All the workers of the plan were being instructed by the chief engineer

13. They can’t make tea with cold water.

⇒ Tea can't be made with cold water.

14. Somebody has taken some of my books away.

⇒ Some of my books have been taken away.

15. They will hold the meeting before May Day.

⇒ The meeting will be held before May Day.

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