The document discusses using cleft sentences to emphasize specific information by fronting it. Cleft sentences use introductory "it", "who/that", "what", or "where" clauses to highlight the emphasized information, such as the subject, object, or location. Examples are provided to show how cleft sentences can be used to emphasize different parts of sentences, including the person, thing, place, time, reason, or events. Readers are instructed to practice forming cleft sentences with exercises on specific pages.