The baseball glove that Keith's brother gave him was very old. . The adjective clause that Keith's brother gave him modifies A) the verb gave. B) the noun brother. C) the adjective old. D) the noun baseball glove.
An adjective clause modifies a noun or pronoun. "That" is a word that is often used with an adjective clause. In this case, the adjective clause is "that Keith's brother gave him" so it is modifying the baseball glove.