The history of what we call cinema today began in the early 19th century. At that time, scientists discovered that when a sequence of still pictures was set in motion, they could give the feeling of movement. In the first two decades of its existence, the cinema developed rapidly. In those early days, films were little more than moving photographs, usually about one minute in length. By 1905, however, films were about five or ten minutes long. They used changes of scene and camera positions to tell a story, with actors playing character parts. In the early 1910s, audiences were able to enjoy the first long films, but it was not until 1915 that the cinema really became an industry. From that time, film makers were prepared to make longer and better films and build special places where only films were shown. The cinema changed completely at the end of the 1920s. This was when sound was introduced. The change began in America and soon spread to the rest of the world. As the old silent films were being replaced by spoken ones on the screen, a new cinema form appeared, the musical cinema. Cho e xin ý chính của đoạn anh văn đây với ạ