PASSIVE VOICE

Marietta understood the lesson
The lesson was understood by Marietta. 

pedro listens to the radio. 
The radio is listened by pedro

They are going to speak English. 
English is going to be spoken by them.

 They will speak English. 
 English will be spoken by tem .

 They are speaking English. 
 English is being spoken by them. 

we had spoken English. 
 English had been spoken by us. 

he will have spoken English. 
English will have been spoken by him. 

they have lent  the pool
the pool has been lent by them