1. A note was written on the board by Mai
=> Mai wrote a note on the board.
2.They'll recycle the waste paper in local factorỵ
=> The waste paper will be recycled in local factory 
3.Mr. ba grows vetgetables in his small arden.
=> Vetgetables are grown in Mr.Ba's small garden by him
4.The bicycle has just been repaired by my brother
=> My brother has just repaired the bicycle
5,The artists are painting a big picture in front of the town hall
=> A big picture is being painted in front of the town hall by the artists.