Complex sentence: In 1948, Hall appeared in a film called "A World is Turning", intended to highlight the contribution of black men and women to British society at a time when they were struggling for visibility on the screens.
Split into simpler sentences: In 1948, Hall appeared in a British movie called "A World is Turning". The movie was intended to highlight the contribution of black men and women to British society at a time when they were struggling for visibility on the screens.