[992.] (1 b.) Most verbs in -āre have the perfect stem in -v- ([869]), and the perfect participle in -tus, both preceded by a form of the present stem in long -ā-: as,

laudō, praiselaudārelaudāvīlaudātus
līberō, freelīberārelīberāvīlīberātus
nōminō, namenōminārenōmināvīnōminātus
spērō, hopespērārespērāvīspērātus

PERFECT STEM IN -u-.

[993.] (2.) The following verbs in -āre have the perfect stem in -u ([874]), and the perfect participle, when used, in -tus; in some participles, -tus is preceded by a short i, thus, -itus ([910]):

crepō, rattlecrepārecrepuī(in-crepitus)

Forms of the perfect system in -v- ([823]) are: in-crepāvit (Plaut.), dis-crepāvit (Varr.), in-crepārit (Suet.).

cubō, liecubārecubuī——

Forms of the perfect system in -v- ([823]) are: ex-cubāverant (Caes.), cubāris (Prop.), in-cubāvēre (Plin.), cubāsse (Quintil.). Compound perfect participle in-cubitus (Plin.).

domō, tamedomāredomuīdomitus
ē-necō, murderē-necāreē-necuīē-nectus

The simple verb has necāvī, necātus; twice necuit (Enn., Phaedr.). ē-necō sometimes has i for e in the present and perfect system; once ([823]) ē-nicāvit, and once ([887]) ē-nicāssō (Plaut.); perfect participle also ē-necātus (Plin.).