The document discusses different types of questions in English, specifically object and subject questions. Object questions use auxiliary verbs like "do", "does", or "did" to ask about the object of the sentence. Examples include "What did Christopher Columbus discover?" and "Where did Mary live?". Subject questions do not use auxiliary verbs and ask about the subject of the sentence, such as "Who discovered America?" and "Who lived in Argentina?". The document provides additional examples and a comparison chart of object and subject questions.