41. Classical Irish had a three-way aspectual contrast of simple perfective imperfective in the past and present tenses. 42. In Bulgarian, which has produced a new regular formation, the aorist is used in perfective imperfective aspect. 43. The perfective and imperfective need not occur together in the same utterance; indeed they more often do not. 44. This mutation occurs in imperfective aspect ( present tense ), and in irrealis mood ( future tense ): 45. The unidirectional verb serves as the base for the perfective, and the multidirectional as the base for the imperfective . 46. The indicative mood has five " simple " ( imperfective , conveying an action that occurs repetitively or continuously ). 47. There is a tendency to prefer imperfective verbs in imperative sentences for politeness; negative imperatives quite rarely use perfectives. 48. This mutation occurs in imperfective aspect, and in the presence of the additive marker " mom ": 49. The difference is mainly stylistic : imperfective is neutral here, while using perfective causes stronger tone of the statement. 50. Moreover, all past and remote forms have developed imperfective forms marked by " [ mi-] ".
