Change the sentences from the Active into the Passive Voice

1) They built this house 100 years ago.

2) The children listen to the radio attentively.

3) We have sold the car.

4) Kate will send the letter tomorrow.

1) This house was built by them 100 years ago.2) The radio is listened to attentively by children.3) The car has been sold by us.4) The letter will be sent by Kate tomorrow.