Uberto's Aria "Sempre in contrasti..." --This is Uberto's second aria. It appears to me to be in a composite ternary, part A (in major) being a form of Rondo, B (in minor) having two parts that don't repeat, one very different from A, and the second very similar to parts of A which transitions well back into a repeat of A. With A, he runs through the text twice repeating each line at least once to give emphasis to his frustration. When he repeats, the first part of A (a)is altered and moves around different tonal areas, but returns to the same (b) exactly. This "b" of A also shows up altered and with different words in the "b" of B. I really don't know if it's really a ternary, but since it does seem to divide very clearly into a major A and a minor B (which could stand alone tonally and lacks transition back into A) and then a return of A (though only run through once).
This is one of the earliest pieces of comic opera (evolved from the intermezzo) that is still played regularly in theatres today and was first open in 1733. I was curious because Pergolesi came up in class the other day. La serva padrona is about a servant girl who has been treated so well that she begins to think she has a right to be a noble lady and stops being useful.