Question

They were singing a song change into passive voice​

Answer 1

Answer: A song was being sung by them.

Answer 2

$\color{red} \huge{active \: voice} \\ \\ \color{pink} \bf{they \: were \: singing \: a \: song} \\ \\ \color{blue} \huge{passive \: voice} \\ \\ \color{pink} \bf{a \: song \: was \: being \: sung \: by \: them}$

RULES TO CONVERT ACTIVE VOICE TO PASSIVE VOICE ARE.

1.Interchange subject with object.

2.use helping verb

3.change verb 1st form to 3rd from

4.Use preposition (by).

Hope its helps u all ☺️✌️