1. This room has been painted blue.
The active voice is:

a. The man has been painted blue the room
b. The man has been the room painted blue
c. The man has painted blue the room
d. The man has painted the room blue
e. The man has been painted the room blue

2. Cricket is played in Australia.
The active voice is:
a. People is played Cricket in Australia
b. People is playing Cricket in Australia
c. People was playing Cricket in Australia
d. People play Cricket in Australia
e. People plyed Cricket in Australia

3. They were singing a song in the lesson yesterday.
The passive voice is:
a. They sing a song in the lesson yesterday
b. They sang a song in their lesson yesterday
c. A song is being sung in the lesson yesterday
d. A song was being sung in the lesson yesterday
e. In the lesson a song was sung yesterday

4. We have lost our key.
The passive voice is;
a. Our key have lost by us
b. Our key has lost by us
c. Our key have been lost by us
d. Our key is lost by us
e. Our key has been lost by us

5. You might see dolphins here.
The passive voice is:
a. Dolphins soetimes can be seen here
b. Dolphins might see you here
c. Dolphins might you see here
d. Dolphins might be you seen here
e. Dolphins might be see here by you

6.The report must be completed by next Friday.
The active voice is:
a. We must completed the report by next Friday
b. We must be completed the report by nest Friday
c. We must complete the report by neat Friday