An adjective clause, also known as a relative clause, is a type of subordinate clause that modifies a noun or pronoun in a sentence. Adjective clauses are introduced by a relative pronoun, such as "who," "whose," "that," or "which," and provide additional information about the noun or pronoun they modify.
For example, in the sentence "The man who lives next door is my neighbor," the adjective clause "who lives next door" modifies the noun "man" and provides additional information about him. In this sentence, the relative pronoun "who" acts as the subject of the adjective clause and the verb "lives" is the predicate.
Another example of an adjective clause is "The cat that is sleeping on the couch is mine." In this sentence, the adjective clause "that is sleeping on the couch" modifies the noun "cat" and provides additional information about it. In this sentence, the relative pronoun "that" acts as the subject of the adjective clause and the verb "is sleeping" is the predicate.
Adjective clauses can also be used to provide additional information about possessive nouns or pronouns. For example, "The book whose cover is blue is my favorite." In this sentence, the adjective clause "whose cover is blue" modifies the possessive noun "book" and provides additional information about it. In this sentence, the relative pronoun "whose" acts as the subject of the adjective clause and the verb "is" is the predicate.
It's important to note that adjective clauses are essential to the meaning of a sentence and cannot be removed without changing the overall meaning. In contrast, non-essential adjective clauses, also known as non-restrictive clauses, can be removed without changing the overall meaning of the sentence. These clauses are usually set off by commas and provide additional, but not essential, information about the noun or pronoun they modify.
For example, "My friend, who is a doctor, is coming to visit." In this sentence, the non-essential adjective clause "who is a doctor" provides additional information about the noun "friend," but it is not essential to the meaning of the sentence.
In summary, an adjective clause is a type of subordinate clause that modifies a noun or pronoun in a sentence and provides additional information about it. Adjective clauses are introduced by a relative pronoun and can be either essential or non-essential to the meaning of a sentence.