Between the sections of recitatives there are arias, each of which is sung by one of the four soloists: a soprano, an alto, a tenor and a bass. The arias often have an introductory movement called “arioso” which in musical style is something between a recitative and an aria. The arias are accompanied by the orchestra, often with one instrument playing an important solo. The words of the arioso and arias comment on what is happening in the story and describe what is going on in the people’s minds. 