How to use a comma correctly
A comma can be used for a few different reasons.
To separate items in a list
When a sentence contains a list of three or more items, then we need to put a comma after each item. The ‘item’ can be a noun, verb, or adjective phrase.
The Oxford comma is the comma that comes just before the word ‘and’. Some people prefer to use the Oxford comma while others prefer not to use it; however, either way, is correct.
➜ E.g. Jay bought apples, bananas, oranges, and grapes. ⟶ Oxford comma
➜ E.g. Jay bought apples, bananas, oranges and grapes. ⟶ No Oxford comma
To join two independent clauses
We can use a comma to separate two independent clauses joined by a coordinating conjunction. An independent clause is a clause that makes sense on its own as a full sentence.
I was late to school. ⟶ This is an independent clause.
I missed the bus. ⟶ This is an independent clause.
Instead of having two independent clauses, we can join them together using a coordinating conjunction.
The coordinating conjunctions are: for, and, nor, but, or, yet, & so.
➜ E.g. I was late to school, because I missed the bus.
The comma comes just before the coordinating conjunction.
It is important to remember that a comma is not strong enough to join two independent clauses without a coordinating conjunction. This grammatical mistake is known as a comma splice. Instead, we use a semicolon or a full stop.
To join a dependent clause and an independent clause
As previously noted, an independent clause is a clause that makes sense on its own as a full sentence. On the other hand, a dependent clause is a clause that doesn’t make sense on its own.
I enjoy playing basketball. ⟶ This is an independent clause.
Although I am not very good. ⟶ This is a dependent clause.
When the independent clause comes first, then we do not need to add a comma to join the two clauses.
➜ E.g. I enjoy playing basketball although I am not very good at it.
When the dependent clauses come first, then we must place a comma between the clauses.
➜ E.g. Although I am not very good at it, I enjoy playing basketball.
Separate extra information
A comma can be used to separate any words or phrases from the rest of the sentence that isn’t essential to the sentence’s meaning.
➜ E.g. Ann, who is a short woman, reached the books from the top shelf.
The part ‘who is a short woman’ does not change the meaning of the sentence. It just adds extra information; therefore, it’s correct to use a comma to separate this information from the rest of the sentence.
Before direct speech
A comma can be used to separate a quotation from the rest of the sentence.
If the sentence doesn’t begin with the direct speech, then the comma is placed just before the quotation begins.
➜ E.g. Jane said, “I want to go to the shopping centre.”
Now let’s look at the rules for when the sentence begins with the direct speech. In British English, the comma goes after closing the quotation marks whereas in American English the comma goes before closing the quotation marks.
➜ E.g. “I want to go to the shopping centre”, she said. 🇬🇧
➜ E.g. “I want to go to the shopping centre,” she said. 🇺🇸
These rules only apply when the quote doesn’t end with a question mark or an exclamation mark.
➜ E.g. “Have you eaten?” she asked.
Following a transition word
Sentences can often begin with an introduction connecting it to the previous sentence – this makes the transition between the two sentences smoother.
➜ E.g. Jim forgot to do his homework. Therefore, he got into trouble.