Classical Greek Verb Tenses

Present
e.g. .luo, luomai. The present usually shows the pure verb stem in verbs with strong stems. In many verbs it undergoes drastic phonetical changes due to the union of the thematic vowels to the tense suffixes.
Future
e.g. luso, lusomai, luthesomai. The future has the characteristic s in between the verb stem and the thematic vowels, which gives: verb stem + s (-the- in passive voice) + thematic vowel + personal ending.
Aorist
e.g. .elusa, eluthen, elusamen. The aorist (from a-orizo, aoristos: indefinite, limitless) is the equivalent to the indefinite past in several languages. Its main characteristic is the temporal suffix -sa- (in the active and middle voice) and -the- in the passive voice. The -s- from sa may change to accomodate different stem endings. For example: kopto = ekops (ps = psi)a.