Like any Arabic verb, the imperfect tense does not exist without a subject marker. A subject marker either consists of one part, a prefix, in the first position or, two parts, a prefix and a second marker after the stem. The imperfect tense verb either has a single subject marker or a two-part split one. The two-part split subject marker is in the second person feminine singular, all duals, and all plurals except the first person. The single subject marker is a consonant located in first position, before the stem. In the case of the two-part split subject marker, the second part is located in the penultimate position before the mood marker. Verb stems vary according to the verb form. The relative location of verb constituents, subject markers, stem, and mood marker is not affected by stem variation. There are three moods for Arabic verbs. Their Arabic names are followed by English equivalents: the indicative, the subjunctive and, the jussive.