A.Although music and speech had frequently accompanied film presentations before the 1920s, there was a strong desire to add sound to the films themselves.
B.Because of intense interest in developing and introducing sound in film, the general use of other technological innovations being developed in the 1920s was delayed.
C.The rapid progress in sound technology made possible by the involvement of telecommunications companies transformed the motion picture industry.
D.Japanese filmmakers had developed the technology for creating sound films before directors in Europe and the United States began experimenting with sound.
E.Before the First World War, film directors showed little interest in linking images with recorded sound.
F.The arrival of sound film technology in the United States forced smaller producers in the motion picture industry out of business.