5. Those bridges were built in 1972.
6. Are more trees going to be planted in thar region ?
7. By whom was this letter written ?
8. The floor is cleaned twice a week. 
9. English songs are being sung beautifully.
10. Can that problem be solved by Nam ?

.

1. is
2. is played
3. is called
4. are not allowed
5. is controlled
6. isn't played
7. is made  
8. was enjoyed
9. was banned
10. spent
11. are played
12. are held

5. Those bridges were built by the workers in 1972.

6. Are more trees going to be planted in that region ?

7. By whom this letter was written ?

8. The floor is cleaned by him twice a week.

9. English songs are being sung beautifully.
10. Can that problem be solved by Nam ?

B.

1. is                     

2. is played

3. is called

4. aren't allowed

5. is controlled

6. wasn't played

7. was made

8. was enjoyed

9. was banned

10. spent

11. was played

12. is held