[In traditional grammars durative is named "present", durative past indicative "imperfect"]

7. [-νε-] Only two verbs belong to this category, but one is of prime importance: (ἀφ)ικνέομαι, which has no other stems than (ἀφ)ικ-; the other one has reduplication as well as the suffix –νε-: ὑπισχνέομαι, other stems: ὑποσχ(η)-; the –ο- of ὑπο- disappears before augment: ao M ind 1^st sg ὑπεσχόμην.

For the precise conjugation of these two verbs see contracted conjugation type -ε-.