Subject Complements

Not all verbs describe actions. Linking verbs such as be, become, seem, appear, look, feel, taste, and smell connect the subject to information that describes or identifies it. The element that follows a linking verb to complete that connection is called a subject complement — it complements (completes) the subject rather than receiving an action.

Subject complements come in two main varieties. A predicate noun renames or identifies the subject: Love is a virtue, She became a doctor. A predicative adjective describes the subject: You look nice, He became angry, The soup tastes delicious. In both cases, the complement refers back to the subject — it is not a separate entity, but another way of naming or describing the same thing.

Predicate pronouns work the same way, though they raise a question of formality. In everyday English, we say It's me! using the objective case. Formal English, however, requires the subjective case: It was I. Both are grammatically defensible, but knowing the difference helps you adapt your register. Possessive pronouns can also appear predicatively: That book is mine, The fault is theirs — notice these never take an apostrophe.

Subject complements are not limited to single words. A noun clause can act as a predicate noun: The problem is that we are late. A prepositional phrase can serve as a predicative description after a linking verb: She is in a hurry, He is out of his mind. These constructions add variety and sophistication to your sentences.

It is important to distinguish subject complements from objects. An object receives the action of a transitive verb; a subject complement follows a linking verb and describes the subject. Compare She called the doctor (object — the doctor receives the calling) with She became a doctor (subject complement — she and the doctor are the same person). The verb type is your guide: action verbs take objects, linking verbs take complements.

A final distinction worth mastering is attributive versus predicative position. An adjective is attributive when it sits before the noun (the red car) and predicative when it follows a linking verb (The car is red). Most adjectives can appear in both positions, but a handful — including asleep, awake, afraid, alive — are restricted to predicative use only. You can say The baby is asleep but not the asleep baby.