TOEFL Listening: TPO-TOEFL阅读TPO - 0J3157M5QGS3P44CN$

According to paragraph 1, which of the following is the most significant development in the history of film? A. The technological innovation of sound film during the 1920s B. The development of a technology for translating films into other languages C. The invention of a method for delivering movies to people's homes D. The technological improvements allowing clearer images in films