The Battle of Grand Gulf was fought on April 29, 1863, during th: English verbs are inflected for tense and aspect and marked for agreement with present-tense third-person singular subject. Only the copula verb to be is still inflected for agreement with the plural and first and second person subjects.[183] Auxiliary verbs such as have and be are paired with verbs in the infinitive, past, or progressive forms. They form complex tenses, aspects, and moods. Auxiliary verbs differ from other verbs in that they can be followed by the negation, and in that they can occur as the first constituent in a question sentence.[198][199]