This document discusses the passive voice, including its definition, how it differs from the active voice, how to convert sentences from active to passive voice, and the various tenses of the passive voice. Specifically, the passive voice occurs when the object of the sentence becomes the subject and a form of "to be" plus the past participle of the main verb are used. The document also notes some sentences cannot be converted to the passive voice if they contain intransitive verbs. It concludes by explaining the passive voice is used when the subject is unknown, irrelevant, or obvious, or the focus is on the verb or object rather than the subject.