| ferveō, boil | fervēre | fervī, ferbuī | —— |
Sometimes with forms in -ere ([821]) in verse. The perfect system is rare.
| prandeō, lunch | prandēre | prandī | prānsus |
[(B.) PERFECT STEM IN -s-, OR IN -v- OR -u-.]
PERFECT STEM IN -s-.
[999.] (1 a.) The following verbs in -ēre have the perfect stem in -s- ([868]), and the perfect participle, when used, in -tus:
| augeō, increase | augēre | auxī | auctus |
| in-dulgeō, am kind | in-dulgēre | in-dulsī | —— |
| lūceō, beam | lūcēre | lūxī | —— |
| lūgeō, mourn | lūgēre | lūxī | —— |
| torqueō, twist | torquēre | torsī | tortus |
[1000.] (1 b.) The following verbs in -ēre have the perfect stem in -s- ([868]), and the perfect participle, when used, in -sus ([912]):
| algeō, feel cold | algēre | alsī | —— |
| ardeō, blaze | ardēre | arsī | —— |
| cō-nīveō, wink and blink | cō-nīvēre | cō-nīxī, cō-nīvī | —— |
The perfects cō-nīxī (Turp.), cō-nīvī (Crass.), occur once each.