Sonata form

Sonata has a form.
1. EXPOSITION, including first theme, transition, second theme, and coda.
2. DEVELOPMENT. This part is like a solo part in modern music. This is where the composer show off his composing ability. That's why this part is normally complicated, jumping from one chord to another.
3. RECAPITULATION. Here is the summary of the song. We will go back to the first theme, transition, second theme, and coda.