1. In a list
2. To separate parts of a sentence (such as a main and sub-clause)
In a list
A comma separates things in a list.
She likes to eat cake, chocolate, and sweets.
Last year he went to Beijing, Seoul, and Tokyo.
The children ran, jumped, and generally didn’t listen to the teacher.
To separate parts of a sentence
If you want to add another clause to a sentence, a comma is a good way to show where each clause is.
I took her to the doctor, who said she had the flu.
If I had a million dollars, I would go around the world.
There are some people, such as Mr Jones, who I respect a lot, but there are other people whom I don’t.
Put commas in these sentences:
1. She has a big fat red cat.
2. The car which he only bought last week has already broken down.
3. His personal ad said he was attractive funny rich a good listener and liked long walks on the beach. Really he is ugly dull poor talks too much and likes short walks to the bar.
4. Running like a polar bear on fire she got to school just before the bell but then realised she had left her homework on the kitchen table.