Question

change to active voice- the light was switched off by them. ​

Answer 1

The sentence can be changed into active voice as follows:

They switched off the light.

What is an active voice sentence?

• Such a sentence, in which the subject of the sentence acts upon the verb of the sentence is referred to as active voice sentence.
• To change a sentence from passive voice to active voice, the object and subject are interchanged, auxiliary form of 'to be' is eliminated, the main verb is changed into the tense on the auxiliary verb of the passive voice sentence.

Answer 2

Question. change to active voice- the light was switched off by them.

Answer. They switched off the light.