For example, the very frequently used aorist, though a functional preterite in the indicative mood, conveys historic or 'immediate' aspect in the subjunctive and optative. The perfect in all moods is used as an aspectual marker, conveying the sense of a resultant state. E.g. ὁράω – I see (present); εἶδον – I saw (aorist); οἶδα – I am in a state of having seen = I know (perfect).