Movie trailers or previews are film advertisements for films that will be exhibited in the future at a cinema, on whose screen they are shown. The term "trailer" comes from their having originally been shown at the end of a film programme. That practice did not last long, because patrons tended to leave the theater after the films ended, but the name has stuck. Trailers are now shown before the film (or the A movie in a double feature program) begins.Trailers normally consist of a series of selected shots from the film being advertised. Since the purpose of the trailer is to attract an audience to the film, these excerpts are usually drawn from the most exciting, funny, or otherwise noteworthy parts of the film but in abbreviated form and without producing spoilers. For this purpose the scenes are not necessarily in the order in which they appear in the film.
