The Difference Between Dependent and Independent Clauses
Grammar teachers will sometimes talk about dependent clauses and independent clauses. What’s the difference between them? On what is a clause dependent or not dependent?
First, let's start with the word clause. A clause is a part of a sentence that contains a subject and some kind of predicate. The sentence “After the rain stopped, we went out on our bikes” contains two clauses: “the rain stopped” and “we went out on our bikes.” The subjects rain and we are given something to do, thereby completing the idea.
By definition, a dependent clause does not form a simple sentence by itself. Also called a subordinate clause, it is connected to the main clause of a sentence by a sentence conjunction such as that or when.
Take this example:
I went out on the bike that Mary gave me for my birthday.
The main clause of the sentence is “I went out on the bike”—a complete idea that can stand on its own as a complete sentence. The words that follow (“that Mary gave me for my birthday”) are a dependent clause, acting subordinate to the main clause. They contain a complete idea in their own right, including a subject and corresponding verb (“Mary gave”), but the existence of the subordinating conjunction that indicates that the clause cannot stand on its own as a sentence. It depends on the main clause, because the main clause contains the object (“bike”) that the verb in the dependent clause (“gave”) targets.
An independent clause, in contrast, can stand alone as a complete simple sentence even though it is usually functioning as part of a larger sentence. For a sentence to be complete, all it needs is a subject and a verb: “She sighed.” No part of the sentence depends on some element expressed outside the sentence.
In many cases, in fact, the only thing that distinguishes an independent clause from a dependent clause is the presence of a subordinating conjunction. Consider what the addition of a subordinating conjunction does to these examples:
Independent: We arrived early to the party.
Dependent: when we arrived early to the party
Full sentence: The host was surprised when we arrived early to the party.
Independent: The store doesn’t open until 10:00 AM.
Dependent: since the store doesn’t open until 10:00 AM
Full sentence: Since the store doesn’t open until 10:00 AM, we have time to get some breakfast first.
Independent: The forecast calls for rain.
Dependent: although the forecast calls for rain
Full sentence: Although the forecast calls for rain, we are going ahead with our plans for the hike.
The dependent clauses in these examples make no sense on their own as complete thoughts, because the subordinating conjunctions that are attached to them (when, since, although) depend on information outside of the clause. (They do, however, all seem like pretty normal text messages.)