Question

what is the passive of bullet killed the dog ​

Answer 1

The given sentence is in the active voice, as the subject 'Julia' performs an action 'rescued' against the object 'three cats'.

If this sentence is changed to passive voice, then the subject is also changed, in order to retain the meaning of the sentence.

So, the object takes the place of the subject and vice versa and the word 'by' is introduced as now the subject receives the action by the object. The verb form of the sentence is also changed from active form to passive.