[869.] (1.) Some verbs in -ere, with vowel roots, and almost all verbs in -āre or -īre, form their perfect stem by adding the suffix -v- to a theme ending in a long vowel: as,
| Perfect Stem. | Verb. | From Theme. |
|---|---|---|
| crē-v- | crēscō, grow | crē- |
| laudā-v- | laudō, praise | laudā- |
| audī-v- | audiō, hear | audī- |
For other verbs in -ere with a perfect stem in -v-, and particularly terō, cernō, spernō, and sternō, see [962-970].
[870.] A few verbs in -ere have a perfect stem in -v- attached to a presumed theme in long ī: as, cupiō, want, cupīvī; petō, aim at, petīvī; quaerō, inquire, quaesīvī; arcēssō, fetch, arcēssīvī; see [966-970].
[871.] A few verbs in -ēre also have a perfect stem in -v-: as, fleō, weep, flēre, flēvī; see [1001-1003]. And three verbs in -ēscere have a perfect stem in -v- attached to a presumed theme in long ē: -olēscō, grow, -olēvī; quiēscō, get quiet, quiēvī; suēscō, get used, suēvī.
[872.] One verb in -āscere has a perfect stem in -v- attached to a presumed theme in long ā: advesperāscit, it gets dusk, advesperāvit.
[873.] (2.) Many verbs in -ere form their perfect stem by adding the suffix -u- to a consonant root: as,
| Perfect Stem. | Verb. | From Theme. |
|---|---|---|
| al-u- | alō, nurture | al- |
| gen-u- | gignō, beget | gen- |
Other examples are: colō, cultivate, coluī; cōnsulō, consult, cōnsuluī; -cumbō, lie, -cubuī; fremō, roar, fremuī; ēliciō, draw out, ēlicuī; molō, grind, moluī; rapiō, snatch, rapuī; serō, string, -seruī; stertō, snore, -stertuī; strepō, make a racket, strepuī; texō, weave, texuī; volō, will, voluī; compescō, check, compescuī ([855]); see [971-976].
[874.] Some verbs in -āre also have a perfect stem in -u-: as, crepō, rattle, crepāre, crepuī ([993]); and many in -ēre: as, moneō, warn, monēre, monuī: see [1004-1006]; also four in -īre: as, saliō, leap, salīre, saluī ([1019]).