4. Perfect Infinitive,
- (Passive.)
Apparently from the same stem, though really of different origin, are the Supine, the Future Active Participle, the Future Infinitive Active and Passive.
THE FOUR CONJUGATIONS.
[98]. There are in Latin four regular Conjugations, distinguished from each other by the vowel of the termination of the Present Infinitive Active, as follows:—
CONJUGATION. | INFINITIVE TERMINATION. | DISTINGUISHING VOWEL. |
| I. | -āre | ā |
| II. | -ēre | ē |
| III. | -ĕre | ĕ |
| IV. | -īre | ī |
[99]. PRINCIPAL PARTS. The Present Indicative, Present Infinitive, Perfect Indicative, and the Perfect Participle[[28]] constitute the Principal Parts of a Latin verb,—so called because they contain the different stems, from which the full conjugation of the verb may be derived.
CONJUGATION OF SUM.
[100]. The irregular verb sum is so important for the conjugation of all other verbs that its inflection is given at the outset.