The document discusses different types of clauses and sentences. It defines main clauses as complete thoughts that can stand alone, and dependent clauses as incomplete thoughts that rely on a main clause. Sentence structures are categorized as simple with one clause, compound with two independent clauses joined by a conjunction, and complex with an independent clause joined to one or more dependent clauses. Common coordinating conjunctions like for, and, nor, but, or, yet, and so are provided with examples to form compound sentences. A list of subordinating conjunctions is also included. Different types of complex sentences such as adjective clauses, noun clauses, and adverbial clauses are briefly introduced.