A complement is a word or group of words that completes the predicate of a sentence. There are four main types of complements: predicate nominative, predicate adjective, direct object, and indirect object. A predicate nominative renames or identifies the subject and follows a linking verb. A predicate adjective modifies the subject and also follows a linking verb. A direct object receives or shows the result of an action verb. An indirect object indicates "to whom" or "for whom" and precedes the direct object after an action verb.