Here are the sentences you provided, converted into passive voice:

1. The floor is cleaned by my mother every day.
2. I am taken to the airport to work twice a week by him.
3. The flowers are picked up in the morning by them.
4. Books are read by her in her free time.
5. Stories are often told to my children by me.
6. A good song was sung by him.
7. His uncle was visited by him yesterday.
8. A new house was bought by us.