`12.` The chief engineer was instructing all the workers of the plant.
`->` all the workers of the plan were being instructed by The chief engineer
`13.` Somebody has taken some of my book away.
`-> `some of my book have been taken away
`14.` They will hold the meeting bofore May Day.
`->`the meeting will be held bofore May Day.
`15. `They have to repair the engine of the car.
`-> `the engine of the car has to be repaired
`16.` The boys broke window and took away some pictures.
`->`the window was broken and some pictures were taken away by the boys
`17.` People spend a lot of money on advertising everyday.
`->` a lot of money is sent on advertising everyday.
`18.` They may use this room for the classroom.
`->` this room may be used for the classroom.
`19.` The teacher is going to tell a story.
`->`a story is going to be told by the teacher
`20.` Mary is cutting the cake with a sharp knife.
`->` the cake is being cut with a sharp knife by Mary.
`21.`The children looked at the woman with a red hat.
`→`The woman was looked at with a red hat by the children
`22.`They have provided the victims with food and clothing.
`→ `The victims have been provided with food and clothing
`23.`People speak English in almost every corner of the world.
`→` E is spoken in almost every corner of the world
`24.` You mustn’t use this machine after 5:30 p.m.
`→` This machine mustn't be used after 5:30 p.m
`25.`After class, one of the students always erases the chalk board
`→`After class, the chalk board is always erased by one of the students