Clause is a group of words with a subject and a predicate. A main, or independent, clause can stand alone as a complete sentence. For example, “We were practicing” is both a main clause and a sentence. A subordinate, or dependent, clause cannot stand alone and functions as (1) a noun, (2) an adjective, or (3) an adverb. Each kind of subordinate clause typically begins with a particular kind of word.
Noun clauses often begin with the word that. In the sentence “They knew that we were practicing,” the noun clause is that we were practicing. The clause serves the noun function of being the direct object in the sentence. Sometimes the beginning word can be deleted: “They knew we were practicing.” But we were practicing is still a noun clause. A noun clause may serve other noun functions. In “That we were practicing was obvious to everyone,” the clause that we were practicing is the subject of the sentence.
An adjective clause is commonly known as a relative clause. It usually begins with a relative pronoun, and it modifies a noun. In the sentence “The musicians who were practicing sounded marvelous,” the relative clause is who were practicing. It begins with the relative pronoun who and modifies the noun phrase the musicians. Other words that are often used as relative pronouns are that, which, whom, and whose.
Adverb clauses begin with subordinating adverbial conjunctions and act as adverbs. Frequently used subordinating adverbial conjunctions include after, when, while, where, wherever, and because. Adverbs often tell when, where, or why an action occurred. In “While we were practicing, they listened,” the adverb clause while we were practicing performs the adverbial function of telling when they listened.
