Question

voice change = clean the room once​

Answer 1

Answer:

Let the room be cleaned once

Answer 2

Answer:

The room is cleaned once.

Explanation:

The above sentance do not have any subject. So for changing voice, we will change the object (The room) and make its subject

"Is" a helping verb is added because the given sentance is a present tense.

Then change the form of verb i.e. clean to cleaned.

The word *once* will remian at its previous place.