You probably use subject complements correctly all the time, without necessarily knowing that’s what they’re called. That’s because they always appear in sentences with linking verbs, and whenever you talk or write about what a subject is or is like (as opposed to what a subject does—for that, you need an action verb), you’re probably using a linking verb. The subject complement is an essential part of the equation—it’s what the linking verb connects to the subject.
In this guide, we’ll dive deeper into types of subject complements, the roles they can play in a sentence, how to use them, and when to avoid them.
What is a subject complement?
A subject complement is a word or phrase that appears after a linking verb in a sentence and is closely related to the sentence’s subject—identifying, defining, or describing it. A subject complement’s job, along with a linking verb, is to clarify the subject of a sentence. Subject complements never appear without linking verbs, and linking verbs never appear without them. In the following examples, the linking verbs are underlined, and the subject complements are in bold.
- The tree we sit under in the park is an oak.
- Oona is always early for appointments.
- That curry smells delicious.
- Their job was becoming more and more difficult to do.
Types of subject complements
Subject complements can be predicate adjectives, predicate nouns, or predicate pronouns.
Predicate adjectives
An adjective that follows a linking verb and modifies the subject of the sentence is a predicate adjective subject complement. It can be a word or a phrase.
- The view from here is gorgeous.
- I felt extremely uncomfortable in the itchy sweater I wore.
Predicate nouns
When a noun—or noun phrase—follows a linking verb and identifies or tells you more about the subject of the sentence, it is a predicate noun subject complement.
- The piece of paper left on the table turned out to be a letter.
- Hiking to the summit of the mountain seemed a rewarding adventure.
Predicate pronouns
When the subject complement of a sentence is a pronoun, there’s a traditional, more formal way to write the sentence and a more casual way that’s increasingly acceptable, especially in spoken English. The formal way is to use the subjective case:
It was either she or I who got there first.
The informal way is to use the objective case:
It was either her or me who got there first.
Subject complements vs. direct objects
Although subject complements and direct objects both come after verbs, they operate differently. Unlike subject complements, direct objects work with transitive verbs; rather than modifying the subject of a sentence, they identify who or what receives the action of the verb. Here are two examples to demonstrate the difference:
The quiche tasted even better the next day.
The toddler tasted the snowflake.
In the first sentence, tasted is a linking verb, and even better is the subject complement describing quiche, the subject. In the second, tasted is an action verb, and snowflake is its direct object. One easy way to tell the difference is to try swapping in the most common linking verb, to be. “The quiche was even better the next day” makes sense, so we know the first sentence is a linking verb/subject complement sentence. “The toddler was the snowflake” does not make sense, so that must be a transitive verb/direct object sentence.
Subject complements vs. adverbs
An easy mistake to make is to use an adverb instead of a subject complement in a linking verb sentence. This mix-up usually happens when the verb in a sentence is sometimes an action verb and other times a linking verb; besides taste, which we saw above, verbs such as feel, smell, and look can also serve both functions.
Remember, when a sentence has a linking verb, what follows it—the subject complement—is about the subject, not the verb. Since subjects are nouns or pronouns and adverbs don’t modify those parts of speech, adverbs don’t mix well with linking verbs. Compare these two sentences using feel:
Luz feels badly.
Luz feels bad.
For the first example sentence to be correct, feel would need to be wearing its action verb hat, with the adverb badly describing how Luz performs the physical action of feeling something. In other words, “Luz feels badly” would mean that Luz is bad at feeling things; perhaps they lack sensation in their fingertips. What we actually want to say is that Luz themself is experiencing negative emotions. In the second sentence, feels is a linking verb, and bad is the adjective serving as a subject complement to tell us about Luz’s state of mind.
Subject complements vs. object complements
Subject complements are one of two kinds of complements. A grammatical complement is the part of a sentence’s predicate that describes either the subject or the verb’s direct object. It is essential for completing the sentence’s thought. As we’ve seen, subject complements fill out our understanding of a sentence’s subject. In the following sentence, the adjective phrase boisterous and entertaining is a subject complement, since it modifies the subject, dinner parties, by way of the linking verb are:
- Dinner parties at Maeve and Killian’s apartment are boisterous and entertaining.
The other kind of complement is called an object complement. Its job is to describe the direct object of a transitive verb. In the next example, the adjective blue operates as an object complement by modifying walls, which is the direct object of the sentence’s verb, painted:
- Maeve and Killian painted their walls blue before the last party they hosted.
More subject complement examples
Here are a few more examples of sentences using linking verbs and subject complements:
- You seem upset. Is everything OK?
- Whatever is in the oven smells divine.
- The philosophy test we took today appeared much more difficult than it actually was.
- We are unlikely to get there before seven.
Subject complement FAQs
What is a subject complement?
A subject complement is a word or phrase that appears after a linking verb in a sentence and modifies the subject of the sentence. A sentence that contains a linking verb is incomplete unless it also contains a subject complement.
- The day became rainy without much warning.
What parts of speech can function as subject complements?
Most of the time, subject complements are adjectives, adjective phrases, nouns, noun phrases, or pronouns.
- Your cat looks friendly.
- That style of music is her favorite.
- The painter I was telling you about is her.
What’s the difference between a subject complement and an object complement?
A subject complement modifies the subject of a sentence with a linking verb.
- That baby feels comfortable with his grandparents.
An object complement modifies the direct object of a transitive verb.
- The baby’s grandparents made him comfortable in his crib.
How do I know when to use an adverb instead of a subject complement?
Use an adverb to modify an action verb.
- They were talking loudly in the stairwell.
Use a subject complement to modify the subject of a sentence whose verb is a linking verb. Since a subject is a noun or pronoun, it can’t be modified by an adverb. In the following sentence, the subject complement is the adjective phrase really loud:
- Their talk in the stairwell was really loud.
