Ok... sorry for the repetition with this piece here... I had it all analyzed by 8 pm... but of course I had to watch Lost and Americal Idol (tehehe) so the post is coming a little late.
This is an example of simple ternary form. The A section is made up of an asymmetrical contrasting period. The first phrase cadences in measure 7 with a half cadence. The second phrase cadences on a PAC in Bb Major in measure 19. The next 3 measures can be considered a cadential extension that helps transition into the B section. The dynamic changes from piano to forte during the extension, which makes the piano B section even more effective and noticable. The A section is considered closed, because it ends in the original key of Bb Major.
The B section brings a change in tonality to the key of g minor. There isn't a strong tonal center here, and no real strong antecedent/consequent feeling, so I call it a phrase group. The B section ends on a PAC in the key of c minor. I consider this to be simple ternary form because the B section is harmonically dependent on the A section, and couldn't survive all by itself. There ya have it.