This document discusses the differences between subjects, objects, and possessive forms. It then explains that "who" is a subject pronoun used to ask which person does an action, "whom" is an object pronoun used to ask which person receives an action, and "whose" is a possessive pronoun used to indicate possession. Examples are provided to illustrate the proper uses of "who", "whom", and "whose" in questions, indirect questions, and adjective clauses.