Voice of Present Progressive Tense

Rules-

Sentence
Structure of making Present Progressive Tense
Structure of converting Present Progressive Tense (Active Voice) to Passive Voice
Positive
Sub +Is/Are/Am + Verb (Ist form)-ing + Obj + Extra Word.
Obj/Sub+ Is/Are/Am + being + Verb (3rd form) + By + Sub/Obj + Extra Word.
Negative
Sub +Is/Are/Am + not + Verb (Ist form)-ing + Obj + Extra Word.
Obj/Sub + Is/Are/Am + not + being + Verb (3rd form) + By + Sub/Obj + Extra Word.
Interrogative
Is/Are/Am + Sub + Verb (Ist form)-ing + Obj + Extra Word?
Is/Are/Am + Obj/Sub + being + Verb (3rd form) + By + Sub/Obj + Extra Word?
Voice of Present Progressive Tense
Voice of Present Progressive Tense 

Examples-

Active Voice
Passive Voice
I am eating a mango.
A mango is being eaten by me.
They are singing songs.
Songs are being sung (by them).
He is helping his mother.
His mother is being helped by him.
She is vexing me.
I am being vexed by her.
They are doing it.
It is being done by them.