The document discusses the passive voice in English grammar. It defines the passive voice as occurring when the subject of the sentence receives the action rather than performs it. The passive voice is used when the doer of the action is unknown, unimportant, or obvious from context. It is formed by using the verb "to be" plus the past participle of the main verb. Some examples of active and passive voice constructions are provided for comparison. Finally, some online exercises for practicing active and passive voice transformations are recommended.