The document discusses clauses and phrases. It defines a phrase as a group of related words that does not contain both a subject and a verb, while a clause contains both a subject and a verb. There are two main types of clauses: independent clauses, which can stand alone as a sentence, and subordinate clauses, which cannot stand alone and must be combined with an independent clause. The document provides examples of identifying phrases, clauses, and different clause types in sentences. It also covers connecting clauses using coordinating and subordinating conjunctions.