The document discusses different types of sentences in English grammar: assertive sentences, interrogative sentences, imperative sentences, and exclamatory sentences. It also discusses negative sentences, which contain words expressing negation like "no", "not", "none", "nothing", and "never". Negative sentences can be formed by using "not" after auxiliary or modal verbs, or with contractions like "isn't" or "didn't" along with verbs like "do", "does", and "did". Examples of different sentence types are provided.