The document discusses subjects and predicates in sentences. It explains that every sentence has two parts: a subject and a predicate. The subject is who or what the sentence is about, and the predicate tells what the subject is or does through a verb. It provides examples of subjects and predicates and discusses the types of verbs: action verbs, helping verbs, and linking verbs. Linking verbs connect the subject to an adjective or another noun rather than expressing an action.