[844.] Root verbs have a root as imperative stem ([745-780]): as, es, &c., fer, &c. But the imperative of nōlō has a stem in -ī-, like verbs in -īre: thus, nōlī, nōlī-tō, nōlī-te, nōlī-tōte.
[845.] The imperative stem of verbs in -ere, and of verbs in -āre, -ēre, and -īre, is the same as that of the indicative: as,
rege, regi-tō, regu-ntō, rege-re; cape, capi-tō, capiu-ntō; fī; laudā, &c.; monē, &c.; audī, &c.
[846.] The second person singular imperative active of dīcō, dūcō, and faciō, is usually dīc, dūc, and fac, respectively, though the full forms, dīce, &c., are also used, and are commoner in old Latin. Compounds of dūcō may have the short form: as, ēdūc. ingerō has once inger (Catull.). sciō has regularly the singular scī-tō, plural scī-tōte, rarely scī-te.
[847.] The imperfect indicative stem ends in -bā-, which becomes -ba- in some of the persons: as,
daba-m, dabā-s, daba-t, dabā-mus, dabā-tis, daba-nt; ība-m; quība-m. In verbs in -ere and -ēre, the suffix is preceded by a form ending in -ē-: as, regēba-m; monēba-m; so also volēba-m (nōlēba-m, mālēba-m), and ferēba-m; in verbs in -iō, -ere, and in -iō, -īre, by a form ending in -iē-: as, capiēba-m; audiēba-m; in verbs in -āre, by one ending in -ā-: as, laudāba-m. In verse, verbs in -īre sometimes have -ī- before the suffix (Plaut., Ter., Catull., Lucr., Verg., &c.): as, audība-t. āiō, say, has sometimes a͡iba-m, &c. ([787]).
[848.] The suffix of the imperfect indicative of sum, am, is -ā-, which becomes -a- before -m, -t, and -nt ([35, 2, 3])the s becomes r between the vowels ([154]): era-m, erā-s, era-t, erā-mus, erā-tis, era-nt.
[849.] The imperfect subjunctive stem ends in -rē-, which becomes -re- in some of the persons: as,