What distinguishes passive voice from active voice in terms of subject role?

In passive voice constructions, the subject is the recipient of the action rather than the performer. This means that the focus shifts from who is doing the action to who is receiving it. For instance, if you take the sentence "The ball was thrown by the boy," "the ball" is the subject receiving the action of being thrown, whereas "the boy" is the agent performing the action but is made secondary in the sentence structure.

This contrasts sharply with active voice, where the subject directly performs the action, creating a more straightforward and dynamic sentence. In passive voice, the agent may even be omitted altogether, emphasizing the action itself or the object receiving the action. Therefore, identifying the passive voice relies on recognizing that the subject's role is to receive the action rather than carry it out.