The document discusses different types of clauses: 1) Adverb clauses use subordinating conjunctions like when, before, and until to modify verbs or provide additional information about time, place, or reason. 2) Adjective clauses use relative pronouns like who, which, and that to modify nouns and provide essential or nonessential information about the noun. 3) Noun clauses function as nouns and can be used as subjects, objects, or objects of prepositions in sentences. They are introduced by subordinating conjunctions like that, what, whether, and if.