The document defines negative sentences and discusses their formation and examples. It begins by defining a negative sentence as one that indicates something is not happening, no longer exists, or does not have a particular quality. It then discusses the main ways to form negative sentences, including using words like "not", changing verbs to their negative forms, and using words like "no", "none", etc. The document also discusses understatement as a form of negative sentence through litotes, providing literary examples. It concludes by checking the reader's understanding of litotes through example negative sentences.