2. The stem is the basic part of the inflected word. To this are appending the various signs, as above, which in verb analysis must again be cut off. E. g., τι-μά-ω, I honor, stem τῑμᾰ. Bt. 157-61; Gl. 248; Gn. 404-7, 153; H.A. 153.
3. The tenses of the verb are called primary or secondary as they have to do with present (or future) or past time. Taking the verb λύω as a model we have:
| Primary | Secondary |
| Present, stem λυ- | Imperfect, stem ἐ-λυ |
| Future, stem λυσ- | Aorist, stem ἐ-λυς |
| Perfect, stem λε-λυκ- | Pluperfect, stem ἐ-λε-λυκ |
| Future perfect, stem λε-λυσ | |
| Bt. 162; Gl. 311; Gn. 717; H.A. 372. | |
4. The future tenses (future, future perfect) are indicated by a σ(+ ο/ε) appended to the stem, as λύ-ω, λύ-σω, λε-λύ-σ-ο-μαι, λύ-θή-σ-ο-μαι. Bt. 212; Gn. 662; Gl. 277; H.A. 372.
5. The perfect tenses (perfect, future perfect, pluperfect) are indicated by (1) the doubling of the stem (i. e., repeating the initial consonant with ε—), and (2) in the active voice by an affixed —κ— (cf. Latin —v—). E. g., λύ-ω perf. λέ-λυ-κα (for λύ-λυ-κα).
Note 1.—If the verb begins with a middle or rough mute, the reduplication occurs with the corresponding smooth mute (cf. I,3). E. g., πέ-φυ-κα (for φέ-φυ-κα). Bt. 162; Gl. 287; Gn. 455; H.A. 300-3.
6. Secondary tenses are indicated generally be the prefix ἐ—, e.g., ἔ-λυ-ο-ν, ἐ-λε-λύ-κ-ε-μεν. In case the verb itself begins with a vowel, the initial vowel is lengthened. E.g., ἀ-κού-ω, ἤ-κου-ο-ν. Bt. 171-2; Gl. 264, 293; Gn. 465, 3; H.A. 354-7.
7. The theme vowel immediately follows the stem. In the indicative it is —ο— before μ and ν, otherwise —ε—; in the subjunctive, —ω—or —η—; in the optative (mode vowel), —οι— or —αι— (aorist passive indicative, —ει—). E. g., ἔ-λυ-ο-ν, ἕ-λυ-ε-ς, λύ-ω-μαι, λύ-η-ται, λυ-οί-μην, λυ-σαί-μην. Bt. 159-60; Gl. 294-5; Gn. 568, 719, 730; H.A. 372.
(1) In aorist tenses except second aorist and aorist passive, the theme vowel is —α—.
(2) In the perfect active the them vowel is —α—, in the pluperfect active it is —ε—.