Question

they sang a poem( change in passive voice)​

Answer 1

A Poem Was sung by them ...

Answer 2

Question :

they sang a poem( change in passive voice)

Answer :

A poem was sung by them.

Rules for changing active to passive :

Identify the subject, the verb and the object: S+V+O.

Change the object into subject.

Put the suitable helping verb or auxiliary verb.

Change the verb into past participle of the verb.

Add the preposition "by“

Change the subject into object.