The document discusses converting sentences from active to passive voice. It provides examples of sentences in active voice and their equivalent passive voice forms. Converting to passive voice is useful when the doer of the action is unknown, unimportant, or when wanting to focus on the action itself rather than who performed it. Examples of conversions include changing "We speak English here" to "English is spoken here" and "They are building a new school" to "A new school is being built."