31. Modern Greek distinguishes the perfective and imperfective aspects by the use of two different verb stems. 32. Special imperfective verbs express aimless motions. 33. Nkn is also used as the prefix for first-person plural imperfective / present tense verbs. 34. Verbal roots were inherently imperfective ( durative, present ) or perfective ( punctual, aoristic ). 35. Combined with the non-past forms, this expresses an imperfective future and a perfective future. 36. The past contrasts perfective and imperfective aspect, and some verbs retain such a contrast in the present. 37. The imperfective aspect may be fused with the past tense, for a form traditionally called the imperfect. 38. These verbs were the perfective verbs, while the ones that did receive a present tense were imperfective . 39. The imperfective marker alters to some extent to match the sound of the verb it is attached to. 40. Contrast between a perfective and an imperfective verb may be also indicated by stress, e . g.
