Complement

Complement is the term used for a word (or words) which are needed to complete the meaning of an expression.

Most phrases and clauses will include a complement of some kind. If you can't remove it from your sentence, then it's likely to be a complement. This is how complements differ from adjuncts. Adjuncts are optional as they are usually just descriptive. Complements are not optional. They are essential to ensure understanding.

Examples of Complements

Here are some examples of complements (complements shaded):

·         John is weak.

(The adjective weak tells us something about the subject (John). This is an example of a subject complement.)

·         John is a chicken.

(The noun phrase a chicken tells us something about the subject (John). This is another example of a subject complement.)

·         The vote made John's position untenable.

(The adjective untenable tells us something about the object (John's position). This is an example of an object complement.)

·         We voted John chairman.

(The noun chairman tells us something about the object (John). This is another example of an object complement.)

In the examples above, the shaded complements complement either a subject or an object; i.e. they sit alongside either a subject or an object to complete it. So, as you'd expect, a complement that completes a subject is called a subject complement, and one that completes an object is called an object complement. That seems pretty straightforward.

However, it gets more complicated. The term object complement is also widely used for a complement which is an object, and – although less common – the term subject complement is used a complement which is a subject. Look at these examples:

·         The board cut John's salary.

(Here, the noun phrase John's salary is the direct object of the verb to cut. As it is an object and a complement (i.e., essential for understanding), it is also an example of an object complement. It's called an object complement because it is an object and not because it complements one. It actually complements the verb. In a logical world, it would just be called a verb complement.)

·         The board cut John's salary.

(Here, the noun phrase The board is the subjectof the verb to cut. As it is a subject and a complement (i.e., essential for understanding), it is also an example of a subject complement. It's called a subject complement because it is a subject and not because it complements one. It actually complements the verb. In a logical world, it would just be called a verb complement.)

Read more about subject complements.
Read more about object complements.

More Examples of Complements

A complement can also be the word(s) that follow a preposition. For example:

·         With his help.

·         On her own.

Read more about the object of a preposition.

A complement can be the word(s) that form part of phrasal verb. For example:

·         Break down

·         Cross out

·         Get over

·         Tear up

You Can Have Several Complements

In summary, a complement is just the word(s) needed to complete an expression's meaning. Therefore, a sentence will often have several complements. Look at these examples:

·         Send him out.

(The word out is a complement for the verb to send. It completes its meaning.)

·         Send him out.

(The word him is an object complement for the verb to send out. It completes its meaning.)

Here are some more examples:

·         Drinking red wine helps.

(The words red wine are an object complement for the gerund drinking.)

·         Drinking red wine helps.

(The words Drinking red wine are a subject complement for the verb to help.)

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