Ex1: 

1. This flower is watered by my father every morning

2. Fiona was invited to John's birthday party by him last night

3. The dinner is being prepared in the kitchen by her mother

4. our teeth should be cleaned twice a day

5. the english grammar have been explained by our teacher

6. the accident was caused in this city by some drunk drivers

7. Tom's parent will be visited next month

8. the secretary wasn't phoned by the manager this morning 

9. was this beautiful dress bought by Mary?

10. these old pictures won't be hang in the living room

11. this factory wasn't built by the german during the second world war 

12. This house and these cars are going to be painted for christmas day by the greens

13. the cats had been fed by Ann before she went to the cinema

14. the pollution problems have been discussed by the students since last week

15 has the most valuable painting been stolen in the national museum by the thieves 

16. the new president will be interviewed on tv

17. How many language are spoken in canada

18. are those shoes going to be repaired 

19. his nose has been broken in a football match

20. have the above sentences been finished