Orchestras play a wide range of repertoire ranging from 17th-century dance suites, 18th-century divertimentos to 20th-century film scores and 21st-century symphonies. Orchestras have become synonymous with the symphony, an extended musical composition in Western classical music that typically contains multiple movements which provide contrasting keys and tempos. Symphonies are notated in a musical score, which contains all the instrument parts. The conductor uses the score to study the symphony before rehearsals and decide on their interpretation (e.g., tempos, articulation, phrasing, etc.), and to follow the music during rehearsals and concerts, while leading the ensemble. Orchestral musicians play from parts containing just the notated music for their instrument. A small number of symphonies also contain vocal parts (e.g., Beethoven's Ninth Symphony).