Have you ever been confused about how to use a comma? Has your teacher ever said your sentences are too long? Don’t worry, these are typical problems! The rules of comma use are varied and a bit complicated, but we’ll try to give you an overview of some of the most important ones.
Using a comma as a pause
A comma is often thought of as representing a ‘pause’, which separates words, clauses or ideas within a sentence, as opposed to a full stop (“period” in American English), which signifies the end of one sentence. While this is somewhat true, there are actually some specific situations when you should learn to use a comma:
- After a dependent clause in a sentence that also an independent clause.
Remember: “independent” means it can be alone and make sense; “dependent” means it must be with another clause:
When I was at the party…
After I arrived…
As soon as the music started…
These are all dependent, because alone they are incomplete – the conjunctions tell us there is more information to come to finish the story. The comma comes after these clauses, but before the independent clause. The clause isn’t necessary if the dependent clause comes at the end, unless you want added emphasis or are using negation. Therefore:
correct: When I was at the party, I met my new neighbour.
correct: After I arrived, they started playing party games.
correct: As soon as the music started, they started dancing.
correct: I went home before it got too late.
correct: I drank rum and coke, when I saw that they didn’t have wine.
incorrect: They didn’t have wine, I drank coke.
The last example is two independent clauses, and this mistake is known as a “comma splice”. If you want to connect the two clauses, use a conjunction:
correct: They didn’t have wine, so I drank coke.
- Around an appositive
This sounds complicated, but it isn’t! An appositive is just extra information given about a noun in a sentence, for example:
Wrens, a kind of bird, are often found in this area.
My neighbour, a doctor, is having a party tomorrow.
Sometimes appositives are quite long, but they still need a comma! Also, a comma is also used around a non-defining relative clause, which are similar to appositives, but not around defining relative clauses, which provide important or defining information that tells something apart from others in a group. So:
correct: My neighbour, who works at the local hospital, is having a party tomorrow.
correct: My neighbour served Sailor Jerry’s, a type of rum from the carribean that I first tried when I was on holiday there, at his party yesterday.
incorrect: My neighbour, that works in the local hospital, had a party yesterday.
- Use commas to separate items in a list
When you are listing three or more things in a sentence, the comma tells you how to separate these things out into different items:
At the party, there was wine, beer, rum and coke, and snacks. (Here, rum and coke is considered one thing, separate to the others)
There were a few different people at the party: my neighbour, his wife, the man who lives downstairs, and the woman from the top floor. (There were 4 separate people)
The last comma in the list sometimes causes issues, as not everyone agrees that it should be used. It is known as a serial (or Oxford) comma, and is used to show that the last two things in the list are separate, but equal, items in the list (i.e. “rum and coke” and “snacks” are separate, but both served at the party). However, be careful when you want to use an appositive within the list:
There were a few different people at the party: my neighbour, a doctor, his wife, and the man from downstairs. (Was there 3 people, one of them a doctor, or 4 people?)
Because this is unclear, it’s better to phrase it in a different way:
There were a few different people at the party: my neighbour, who’s a doctor, his wife, and the man from downstairs.
This rule also applies to adjectives in a list that all describe the same noun:
It was lovely to meet my neighbour’s wife. She was kind, funny, and charismatic. (Because it won’t cause any confusion, it’s acceptable to omit the last comma here)
- After adverbs and adverbial phrases
Remember – adverbs and adverbial phrases are words that describe how something is done – they give more information about verbs. Adverbs often end in “-ly”, but not always. This rule also applies to conjunctions like “however”, “on the other hand”, “furthermore” and “yes/no”:
correct: Finally, the music stopped and people started going home.
correct, Yes, it was good. However, I wish there had been wine.
correct: Luckily for me, my neighbour had a few extra bottles at home.
- When writing long numbers
In English, every three digits in a long number are separated by a comma, not a full stop, like in other languages:
correct: 1,268 (One thousand, two hundred and sixty eight)
correct: 26,400,212 (26 million, 400 hundred thousand, 2 hundred and twelve)
correct: 45,000.99 (45 thousand point nine nine)
Good luck with your commas! If you’re interested in learning more about commas, punctuation, or how to write well in English, you might want to consider an IELTS preparation or an Academic English course, which should cover these skills.