 But it also depends on the selection of the tense/aspect or mood.Most Semitic languages make a basic two-way distinction between a tense/aspect stem that is conjugated with suffixes and another stem that is conjugated with prefixes and, in some forms, suffixes as well.In Ethiopian Semitic and in Arabic, the first, known as the perfect, is used for past tense, and the second, known as the imperfect, is used for present and sometimes future tenses.