Complex sentence: The piece has a grand introduction with fast ascending chromatic notes in both hands, setting the mood of the piece; it shows the heroic side of Chopin's art. The first theme is a dance-like theme and is in the tonic key of A-flat major.
Split into simpler sentences: The piece has a grand introduction with fast ascending chromatic notes in both hands, setting the mood of the piece. It shows the heroic side of Chopin's art. The first theme is a dance-like theme and is in the tonic key of A-flat major.