Sentence: Those are books that need to be returned to the library
Answer:
<u><em>Books</em></u>
Pronouns are used to replace nouns with more general terms that don't describe a specific person or place. The antecedent of a pronoun is the word that the pronoun replaces.
In the case of this sentence, the pronoun <em>those </em>replaces the word <em>books</em>, therefore the antecedent of the pronoun <em>those </em>is <em>books</em>.
