This piece is rather comlicated, but I'll try to touch on the high points. This is in Ternary form. The A section is measures 1-48, B section 49-76, and then A' til the end.
The A section is in binary form and begins in A major with a half cadence at measure 8. You could say this was a PAC, but I don't feel like it modulates til the next cadence at 16 when it really is a PAC in E major. The b section of the A starts at 17 and can only be described as a phrase group. Then we sort of have a "coda" type thing instead of a return to the a section from m. 38- 48.
The B section begins with a little introduction from m. 49-56. It appears to be in f sharp minor. When we get to the real B section it starts in F# major and uses a cannon-type motion to play around in different keys. Then in measure 65 the B section begins its transition back to A major and finished on a PAC in measure 76.
Then we are back to the A section which is much shorter this time. The song of course ends in a PAC in A major.
I was afraid to get really into this piece because it's sooooo complicated. If someone is looking for a piece to write a good LONG paper on, I suggest this one. I did my best! :-)