A subject complement is a word or phrase that follows a linking verb (such as "is," "am," "are," "was," "were," "seem," "become," etc.) and provides more information about the subject of the sentence. There are two types of subject complements: predicate nominatives and predicate adjectives.
A predicate nominative is a noun or pronoun that renames or identifies the subject of the sentence. It provides more information about the subject.
Example: She is a teacher. In this sentence, "teacher" is the predicate nominative, as it renames the subject "she."
A predicate adjective is an adjective that describes or modifies the subject of the sentence. It provides more information about the subject.
Example: The flowers are beautiful. In this sentence, "beautiful" is the predicate adjective, as it describes the subject "flowers."