Foundations of the second aorist (same perfective aspect as the first aorist, but built on a CHANGED VERB STEM with secondary endings — no -σα formative), a tour of why the stem changes (suppletion: εἶπον from λέγω, ἦλθον from ἔρχομαι, εἶδον from ὁράω) and the high-frequency stem-change verbs, the Step 1/2/3 derivation of ἔλαβον (active) with ἐγενόμην (middle) as supplement, side-by-side comparisons against the first aorist AND against the imperfect (this is the central parsing trap — same endings as imperfect, but different stem), the stem-recognition parsing workflow, and translation practice on the suppletive set. Unlock each subtopic by scoring at least 90% on its mastery check.