What is a complement?

Complements are words or groups of words that are necessary to complete the meaning of another part of the sentence. Complements act like modifiers to add additional meaning to the word or words they are attached to. However, unlike adjunct modifiers, they do not add supplemental information—they provide information that is necessary to achieve the intended meaning in the sentence.
Complements, even those that complete the meaning of the subject, are always part of the predicate.

Types of Complements

There are five main categories of complements: objects, object complements, adjective complements, adverbial complements, and subject complements. We’ll briefly look at each below. To learn more about them, continue on to their individual sections.


Grammatical objects are nouns or pronouns that complete the meaning of verbs and prepositions. Depending on what they complete, objects are also sometimes known as either verb complements or prepositional complements.
There are three types of objects: direct objects, indirect objects, and objects of prepositions.

Direct objects

Direct objects are directly affected by verbs they complete—that is, the verb’s action is happening directly to them. For example:
  • “The dog chased its tail.”
  • “Mary reads a new book every week.”

Indirect objects

An indirect object is the person or thing who receives the direct object of the verb.
For example:
  • “Please pass me the salt.”
  • “I sent the company an application for the job.”

Objects of prepositions

Prepositions also take objects, connecting them back to another element of the sentence to elaborate on its meaning. Together, the preposition and its object form a prepositional phrase. For example:
  • “Your backpack is under the table.”
  • “I got a ticket for speeding.”

Object Complements

An object complement is a word or group of words that describes, renames, or completes the meaning of the direct object of a verb. It can be a noun, adjective, relative clause, infinitive, gerund, or a phrase made from any one of them.

Nouns and noun phrases

When we use nouns as object complements, they serve to rename or re-identify the object of factitive verbs. For example:
  • “The committee elected him treasurer.”
  • “Mrs. Fields named her late husband the executor of her estate.”

Adjectives and adjective phrases

Adjectives that function as object complements serve to describe or modify the direct object. Like all object complements, adjectives must follow the direct object they are describing. If they come before it, they are simply acting as attributive adjectives, which are not necessary to complete the meaning of the sentence.
  • “All he wanted was to make his husband happy.”
  • “The excitement of the day got the kids way too hyper.”

Relative clauses

Relative clauses are dependent clauses that are introduced by relative pronouns. Like adjectives, relative clauses serve to describe the object that they follow; for this reason, they are often called adjective clauses.
For example:
  • “Do you know someone who can work the printer?”
  • “I hate the color that they painted this room.”

Infinitives and infinitive phrases

An infinitive or infinitive phrase acts as an object complement by describing the intended or desired action of the direct object. For example:
  • “I didn’t expect you to approve.”
  • “She’s forcing me to work this the weekend.”

Participles and participle phrases

A participle generally functions as an object complement by describing what the direct object of a factitive verb is or was doing (as opposed to infinitives, which describe an act that has not yet been done).
For example:
  • “We came across him lying in the yard.”
  • “My mother noticed the baby walking by himself.”
  • “All that running around left me exhausted.”

Adjective Complements

An adjective complement (also called an adjective phrase complement) is a phrase or clause that provides information necessary to complete an adjective’s meaning. Adjective complements can be prepositional phrases, infinitives and infinitive phrases, or noun clauses.

Prepositional Phrases

Prepositional phrases describe the relationship between the adjectives they complement and the objects of their prepositions.
  • “I am perfectly content on my own.”
  • “He felt alone in the world.”

Infinitives and infinitive phrases

Infinitives and infinitive phrases describe actions that result from or lead to the adjective they complement.
For example:
  • “I’m very happy to know you!”
  • “We’re just glad to be of service.”

Noun Clauses

A noun clause is a dependent clause that is able to function grammatically like a noun. It connects the adjective’s meaning to an action by a secondary subject.
  • “We were a little curious why they decided to leave.”
  • “I’m thrilled that you are coming to visit!”

Adverbial Complements

Adverbial complements are adverbs or adverbial elements in a clause that are required to complete the meaning of the verb.
Adverbial complements usually describe location or direction, and most frequently occur with verbs that indicate motion. They always appear after the verb they complement.
If the verb is intransitive, the complement will appear directly after the verb; if the verb is transitive, the complement will appear after the verb’s direct object.
For example:
  • “The teacher sent Tim home.”
  • “Please put the book on the shelf.”

Subject Complements

A subject complement is the information that follows a linking verb to describe, identify, or rename the subject of the clause. A subject complement can either be a predicate noun, a predicate pronoun, or a predicative adjective.

Predicate nouns

Predicate nouns serve to rename or re-identify the subject after a linking verb. If the noun is accompanied by any direct modifiers (such as determiners, adjectives, or prepositional phrases), the entire noun phrase acts predicatively.
For example:
  • Love is a virtue.”
  • Tommy seems like a real bully.”

Predicate pronouns

We can also use a predicate pronoun after a linking verb to re-identify the subject. This is most common in questions and responses in which the identity of the subject is not known or is being explained. For example:
  • Question: “Who is it?”
  • Answer: “It’s me!”
We can also use predicate pronouns in declarative statements, but this is less common in everyday speech and writing. For instance:
  • It was I who did this.”
  • “Her husband took all the credit, but it was she who did all the work.”

Predicative Adjectives

A predicative adjective is an adjective used after a linking verb to describe or modify the subject of the clause. For example:
  • You look nice.”
  • He is very handsome.”
When a prepositional phrase follows a linking verb (especially the verb be), it functions in the same way as a predicative adjective to describe the subject. For example:
  • The cat is in the shed.” (The prepositional phrase in the shed is describing the subject the cat.)
  • I am across the street.” (The prepositional phrase across the street is describing the subject I.)

1. What kind of complement is used to create a prepositional phrase?

2. What kind of complement is used to complete an adjective’s meaning?

3. Which of the following sentences uses a subject complement?

4. Which of the following sentences uses an object complement?

5. Identify the adverbial complement in the following sentence:
“I have been living in Ireland for six years.”

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