Voz pasiva primera parte

 PRESENT TENSE: 
He writes a book. 
A book is written by him. 

PAST TENSE: 
I wrote a letter.    
A letter was written by me. 

PRESENT PROGRESSIVE: 
I am eating an apple.   
An apple is being eaten by me. 

PAST PROGRESSIVE:   
I was eating an apple.  
An apple was being eaten by me.