 Complete the following phrase:  The first regular television broadcasts started in 1937. Broadcasts can be classified as recorded or live. The former allows correcting errors, and removing superfluous or undesired material, rearranging it, applying slow-motion and repetitions, and other techniques to enhance the program. However, some live events like sports television can include some of the aspects including slow-motion clips of important goalshits, etc., in between the live television telecast. American radio-network broadcasters habitually forbade prerecorded broadcasts in the 1930s and 1940s requiring radio programs played for the Eastern and Central time zones to be repeated three hours later for the Pacific time zone See: Effects of time on North American broadcasting. This restriction was dropped for special occasions, as in the case of the German dirigible airship 