εἰμί and irregular verbs — foundations of the linking verb and common irregulars; the present indicative paradigm of εἰμί (memorized cold); other tenses and moods (imperfect ἦν, future ἔσται, participle ὤν/οὖσα/ὄν); linking verbs and predicate nominatives (with Colwell's Rule for John 1:1c); οἶδα as the perfect-with-present-meaning verb; other common irregulars (φημί, δύναμαι, κάθημαι, ἔρχομαι); the parsing workflow for irregular verbs; and translation practice with the 14 Lesson 13 vocabulary verbs. Unlock each subtopic by scoring at least 90% on its mastery check.