Asturian grammar is similar to that of other Romance languages. Nouns have three genders (masculine, feminine and neuter), two numbers (singular and plural) and no cases. Adjectives may have a third, neuter gender, a phenomenon known as matter-neutrality. Verbs agree with their subjects in person (first, second, or third) and number, and are conjugated to indicate mood (indicative, subjunctive, conditional or imperative; some others include "potential" in place of future and conditional), tense (often present or past; different moods allow different tenses), and aspect (perfective or imperfective).