Time for some last minute prep for my Advanced Greek course today.
Stan Porter's chapter on the perfect tense is a rich source of information. I agree completely with his view that there are 3 (and not 2) aspects in Greek, that the concept of binary opposition plays a key role, and that a "semantic cline" exists from the least marked to the most marked aspect (aoristic aspect to imperfective acpect to perfective aspect -- using my nomenclature for the aspects).
I like to state the obvious. 😇