As a grammatical term, a complement is a word, phrase, or clause that completes the meaning of the predicate.
The geologist drove a Jeep, [word]
To ride with him is to risk your life, [phrase]
I was surprised that he was so reckless, [clause]
There are four kinds of complements: direct object, indirect object, object complement, and subject complement.
A direct object is a noun or a word group acting as a noun that indicates what or who receives the action of a transitive verb.
She likes chocolate, [noun]
She likes to work, [verbal]
She also likes him. [pronoun]
She likes what she does, [noun clause]
An indirect object is a noun or a word group acting as a noun that indicates to whom or for whom the action of a verb is directed. It accompanies a direct object following particular transitive verbs, such as buy, bring, cause, give, sell, take, tell, and wish.
Tell Camille the story. [Story is the direct object; Camille is the indirect object.]
Fergus gives his dog a new bone every Saturday. [Bone is the direct object; dog is the indirect object.]
An object complement is a noun or an adjective that renames or describes the direct object.
Peggy called him a jerk. [Him is the direct object; jerfe (noun) is the object complement.]
He was making her angry. [Her is the direct object; angry (adjective) is the object complement.]
A subject complement is a word or a word group following a linking verb that renames or describes the subject. It may be a predicate nominative or a predicate adjective.
Her boyfriend is a computer scientist. [Boyfriend is the subject; computer scientist (predicate nominative) is the subject complement.]
Her brother is poor. [Brother is the subject; poor (predicate adjective) is the subject complement.]
complete subjects and predicates
A complete subject is the simple subject plus its modifiers.
The impersonal-looking letter from the college held the verdict on her future. [Letter is the simple subject; the phrase is the complete subject.]
A complete predicate is the simple predicate and any objects, modifiers, or complements.
She turned it over nervously in her hands. [Turned is the simple predicate; it is the direct object; over and nervously are adverbs modifying turned; in her hands is a prepositional phrase modifying turned.]
