erfect Stem, from which are formed--
1. Perfect, Pluperfect, and Future Perfect Indicative,
2. Perfect and Pluperfect Subjunctive,
3. Perfect Infinitive,
- (Active.)
III. Participial Stem, from which are formed--
1. Perfect Participle,
2. Perfect, Pluperfect, and Future Perfect Indicative,
3. Perfect and Pluperfect Subjunctive,
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:--

INFINITIVE DISTINGUISHING
CONJUGATION. TERMINATION. VOWEL.
I. -are a
II. -ere e
III. -ere e
IV. -ire i

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.

PRINCIPAL PARTS.
PRES. IND. PRES. INF. PERF. IND. FUT. PARTIC.[29]
sum esse fui futurus

INDICATIVE MOOD.

PRESENT TENSE.
SINGULAR. PLURAL.
sum, _I am_, sumus, _we are_,
es, _thou art_, estis, _you are_,
est, _he is_; sunt, _they are_.

IMPERFECT.
eram, _I was_, eramus, _we were_,
eras, _thou wast_, eratis, _you were_,
erat, _he was_; erant, _they were_.

FUTURE.
ero, _I shall be_, erimus, _we shall be_,
eris, _thou wilt be_, eritis, _you will be_,
erit, _he will be_; erunt, _they will be_.

PERFEC