Step 1: Identify the voice of each sentence.
Both given sentences are in the active voice, where the subject performs the action.
Step 2: Change sentence (a) into passive voice.
Subject: Wild dogs
Object: pets
Tense: Past continuous
In passive voice, the object becomes the subject and the verb changes to textit{were being + past participle}.
Hence, the sentence becomes: “Pets were being killed by wild dogs.”
Step 3: Change sentence (b) into passive voice.
Subject: I
Object: a sweeper-boy
Verb: know
In passive voice, the object becomes the subject and “to me” is added.
Thus, the sentence becomes: “A sweeper-boy is known to me.”
Step 4: Conclusion.
By changing the subject and using the correct verb form, both sentences are correctly converted into passive voice.