Can clauses perform as adjectives, adverbs, and nouns?

Parts of the Sentence - Adjective, Adverb, and Noun Clauses. The adjective clause is used to modify a noun or a pronoun. It will begin with a relative pronoun (who, whose, whom, which, and that) or a subordinate conjunction (when and where). Those are the only words that can be used to introduce an adjective clause.