The document discusses the passive voice in English grammar. It provides examples of sentences in both active and passive voice and explains the rules for transforming an active sentence into the passive voice. Specifically, it notes that the object of the active sentence becomes the subject in the passive, the subject becomes introduced by the preposition "by", and the main verb is replaced with a form of "to be" plus the past participle of the main verb. It also provides a table showing how the passive is formed for different verb tenses and includes 5 examples transforming sentences from active to passive voice.