Grammar Lessons: Where to use a comma
Where do you use a comma?
It seems like a weird question to ask, right? Don’t commas just go where you pause in the sentence? Nope. But if you thought that, you’re not alone!
There are a lot of rules that dictate where and when to use a comma, but the two most fundamental rules are related to independent and dependent clauses. Before you can begin to understand where to use a comma, you first need to know the difference between independent and dependent clauses.
What are independent and dependent clauses?
An independent clause is a part of a sentence that contains a subject and a verb and expresses a complete thought. It is, in effect, a complete sentence.
Example: Luke thought he was an orphan.
- Who is our subject? Luke
- What did our subject do? Thought
- What did he think about? That he was an orphan (this is the object)
You don’t need an object to have an independent clause or a complete sentence. “Luke thought” is a perfectly acceptable sentence, but it doesn’t tell the reader very much.
A dependent clause contains a subject and a verb, but does not express a complete thought. Dependent clauses are not complete sentences, and therefore cannot stand alone.
Example: Because he thought he was an orphan.
Even though we have all the components of a sentence here, we don’t have a complete sentence or an independent clause. This is because the statement doesn’t express a complete thought. The “because” at the beginning is throwing everything off!
“Because” is called a “dependent marker.” These words demand more information and tell the reader that there is more to this sentence. When you add “because” to the beginning of a sentence, you automatically have a dependent clause.
Other dependent markers include after, although, before, even if, in order to, since, unless, until, when, whenever and while.
- Independent clause: Luke went on a journey.
- Dependent clause: When Luke went on a journey, …
- Independent clause: Luke met Ben.
- Dependent Clause: After Luke met Ben, …
- Independent clause: Ben wasn’t fully honest with Luke.
- Dependent clause: Since Ben wasn’t fully honest with Luke, …
Now that you understand the difference between independent and dependent clauses, you’re ready to learn two basic comma rules:
1. You use a comma when you have two independent clauses separated by a conjunction:
Example: Luke thought he was an orphan, but he was wrong. A conjunction is a word that connects two clauses. Some popular conjunctions include and, but, or, nor, so, yet, etc. When you use a conjunction to connect two independent clauses, you always put a comma before the conjunction.
2. You also use a comma when you have a dependent clause that comes before an independent clause in a sentence:
Example: Because he thought he was an orphan, Luke was surprised to meet his father and twin sister.
These are only two of many reasons why you would use a comma in a sentence.