The document discusses the passive voice in language. The passive voice constructs the subject as receiving the action of the verb, with the agent, if expressed, appearing in an oblique case. In the passive voice, a transitive verb is converted to an intransitive verb with one principal argument, the patient. In English, the passive is formed with the auxiliary "to be" and the past participle of the verb. The active voice subject becomes the passive voice subject, and the active complement may remain as an optional agent in the passive construction.