This document discusses noun clauses, including their definition, how they are used, and examples of noun clauses functioning as subjects, direct objects, indirect objects, objects of prepositions, and predicate nouns. Noun clauses can function as subjects, direct objects, indirect objects, objects of prepositions, or predicate nouns in a sentence. They are introduced by words like who, what, when, where, why, how, whether, whose, which, whichever, and that. The document provides examples to illustrate each use.