1. Exposition
The exposition presents important musical ideas. In many classical sonata-form movements, the first theme begins in the home key. A transition then moves toward a new key area. The second theme often appears in the dominant key for major-key pieces or in a related major key for minor-key pieces.
2. Development
The development section explores, fragments, sequences, and transforms earlier material. It often moves through several keys and increases tension. This is where composers show how flexible their themes can be.
3. Recapitulation
The recapitulation brings back the exposition material, but now the second theme is usually adjusted to stay in or return to the home key. This creates structural resolution.
4. Coda
A coda is an ending section. Some codas are short confirmations of the home key. Others are large, dramatic conclusions that feel almost like a second development.