This document defines and provides examples of common question words in English including who, what, when, where, why, which, and how. It explains that who refers to a person, what refers to a specific thing or object, when refers to an occasion or moment, where refers to a place or position, why refers to a reason, which refers to a choice or alternative, and how refers to a way, manner, or form. It also provides examples of questions using these question words and defines their basic grammatical structure.