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12. The rules of the games must be observed carefully.
14. People sell newspaper everywhere in the city.
IV/
1. Letters are typed in the office by Mary. 

7. I had not been told about it.
8. Her telephone number isn't known by me.
11. We are given more information by her.
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.
19. A story is going to be told by teacher.

20. A cake is being cut with a sharp knife by Mary.
21. The woman with a red hat was looked at by the children.
22. The victims have been provided with food and clothing.
23. English is spoken in almost every corner of the world.
24. This machine mustn't be used after 5:30 p.m.
25. The chalk board is always erased by one of the students after class.