Form of Noun Phrases
Noun phrases conveying given information typically have very simple or reduced forms. Very often, they appear pronouns and in some cases they can be completely omitted from a sentence. In a conversation in (33), the given information expressed by the noun phrase previously mentioned in Speaker A's question (joe's sister) occurs as the pronoun she in Speaker B's reply. In (34), the entire part of the sentence which is associated with given information, i.e., Joe's sister is talking to, is omitted from Speaker B's reply.