There are two types of clauses. There are independent clauses, and that is a group of words that contains a subject and a verb and in this case expresses a complete thought. For example, if I say, “Jim studied in his room for his chemistry exam,” that statement has a subject and a verb—“Jim studied”—and the rest of it sort of closes the thought. We don’t need any other information to understand that statement. “Jim studied in his room for his chemistry exam.” There’s nothing that is essential to