Question

how to make the passive voice of they were playing cricket in the playground

Answer 1

Cricket was being played in the playground by them .

Answer 2

There are two ways to answer this question,

“Cricket was being played in the playground by them.”

“Cricket was being played by them in the playground.”

Both the forms are logically correct.

When we convert a sentence in the passive form then the subject will become the receiver of the sentence that shows the action.

Hence, in the playground is the place here and is an independent clause.