1 This flower is watered by my father every morning.

2 Fiona was invented to John's birthday party last night.

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

4 Our teeth should be cleaned twice a day.

5 The English grammar has been explained by our teacher.

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

7 Tom's parents will be visited by him 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 hung in the living room by me.

11 This factory wasn't built by the Greens during the Second World War.

12 This house and these cars are going to be painted for Chrismas 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 in the national meseum been stlen by the thieves.

16 The new president will be interviewed on TV by some people.

17 How many languages are spoken in Canada by them?

18 Are those shoes going to be repaired?

19 His nose has been broken in a football match by him.

20 Have above sentences been finished?

21 When will the work be done?

22 How is this problem going to be dealt with?

23 How is this amount of money spent?

24 I wonder whether Susan or Jane will be chosen for the position by the board of directors.

25 How was the lost man found by the police?

1. My father waters this flower every morning.
→ This flower is watered (by my father) every morning
2. John invited Fiona to his birthday party last night.
→ Fiona was invented to John’s birthday party last month
3. Her mother is preparing the dinner in the kitchen.
→ The dinner is being prepared in the kitchen
4. We should clean our teeth twice a day.
→ Our teeth should be cleaned twice a day
5. Our teachers have explained the English grammar.
→ The English grammar has been explained (by our teacher)
6. Some drunk drivers caused the accident in this city.
→ The accident was caused in this city (by some drunk drivers)
7. Tom will visit his parents next month.
→ Tom’s parents will be visited next month
8. The manager didn’t phone the secretary this morning.
→ The secretary wasn’t phoned this morning
9. Did Mary this beautiful dress?
→ Was this beautiful dress bought by Mary?
10. I won’t hang these old pictures in the living room.
→ These old pictures won’t be hung in the living room 
11. The German didn’t build this factory during the Second World War.
→ This factory wasn’t built (by the Greens) during the Second World War
12. The Greens are going to paint this house and these cars for Christmas Day.
→ This house and these cars are going to be painted for Christmas day by the Greens
13. Ann had fed the cats before she went to the cinema.
→ The cats had been fed before Ann went to the cinema
14. The students have discussed the pollution problems since last week.
→ The pollution problems have been discussed since last week
15. Have the thieves stolen the most valuable painting in the national museum?
→ Has the most valuable painting in the national museum been stolen (by the thieves)
16. Some people will interview the new president on TV.
→ The new president will be interviewed on TV 
17. How many languages do they speak in Canada?
→ How many languages are spoken in Canada ?
18. Are you going to repair those shoes?
→ Are those shoes going to be repaired?
19. He has broken his nose in a football match.
→ His nose has been broken in a football match 
20. Have you finished the above sentences?
→ Have above sentences been finished?

21. When will you do the work?
→ When will the work be done?

22. How are you going to deal with this problem?

→ How is this problem is going to be dealt?

23. How do you spend this amount of money?

→ How is this amount of money spent?

24. I wonder whether the board of directors will choose Susan or Jane for the position.

→ I wonder whether Susan or Jane will be chosen for the position by the board of directors

25. How did the police find the lost man?

→ How was the lost man found by the police?

Chúc bạn học tốt, cho mình xin câu trả lời hay nhất nha :D