Question

Transcribir las siguientes oraciones en voz pasiva
50.They gave Bob a CD player for his birthday.
51.The prime minister will give a medal to the winners.
52.She is telling the children a story.
53.They've offered Sally a job.
54.Poisonous chemicals have polluted the river.
55.Doctor Simms is examining her.
56.You must stop him now.
57.Someone gave them free tickets for the concert.

Answer 1

Deber tener en cuenta que en algunas oraciones tienes dos objetos por lo puedes hacer 2 pasivas dependiendo cuál  de ellos se quiera remarcar. 

They gave Bob a CD player for his birthday.
           Bob was given a CD player for his birthday.
           A CD player was given to Bob for his birthday.

The prime minister will give a medal to the winners.
           A medal will be given to the winners.
           The winners will be given a medal. 

She is telling the children a story.
           The children are being told a story. 
           A story is being told to the children. 

They've offered Sally a job.
           Sally has been offered a job. 
           A job has been offered to Sally. 

Poisonous chemicals have polluted the river.
           The river has  been polluted.

Doctor Simms is examining her.
           She is being examined. 

You must stop him now.
           He must be stopped now. 

Someone gave them free tickets for the concert.
           They were given free tickets for the concert. 
           Free tickets for the concert were given to them.