perfect cadence
V - I
perfect ending
plagal cadence
IV - I
not as perfect but an ending
imperfect cadence
I, II, IV, VI - I
half ending
interrupted cadence
V - VI
illusion of perfect ending, but becomes interrupted
where does an imperfect cadence occur
within a passage of harmony, like a comma in a sentence
imperfect: I - V
opposite of perfect cadence, one part stays the same while two parts fall by a step