Question

we saw an army of ants lugging a fly(change the voice).

Answer 1

An army of ants lugging a fly was seen by us.

Answer 2

Changing the voice of a sentence requires the changing of the place of the subject and object illustrated in the statement. We also need to change the form of the verb and add necessary adverbs or auxiliary verbs into the sentence as needed in the sentence. We must remember that the sense conveyed by the statement must not be omitted or altered.

Moreover, the statement after the change in voice is as follows:

"An army of ants lugging a fly was seen by us."

Note: "Saw" changes to "seen" in the converted expression and the meaning is also maintained within the statement even after changing the places of the object as well as the subject.