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—. (3) In the pluperfect middle and passive the theme vowel is omitted. E. g., λε-λύ-σ-α-μεν, λε-λύ-κ-α-τε, ἐ-λε-λύ-κ-ε-μεν, λέ-λυ-μαι, ἐ-λε-λύ-μην. Bt. 201, 222-4; Gl. 279, 288-9, 298; Gn. 669, 682-3, 698; H.A. 428, 446, 459, 461-3. 8. The sign of the passive voice is often —θε—, sometimes lengthened to —θη— in conjugation, e. g., λυ-θή-σ-ο-μαι. Bt. 231-2; Gl. 302; Gn. 707; H.A. 468. 9. The person of the verb is indicated by a letter or syllable (in origin a personal pronoun) added to end of verb. E. g., λύ-ο-μαι, ἔ-λυ-ο-ν. 10. The middle and passive voices are alike except in two tenses, the future and the aorist. Bt. 167; Gl. 263; Gn. 552; H.A. 376-80. 11. There are two sets (or double sets) of personal ending; one set for the active (primary and secondary) tenses, and one for the tenses of the middle and passive (except second aorist and aorist passive). Bt. 166; Gl. 263, 271; Gn. 551-3; H.A. 375. 12. The personal ending may be shown thus: Primary Tenses Sing. { —ω —μαι { —εις —σαι { —ει —ται Dual { —τον —σθον { —τον —σθην