Commas
Created | Updated Sep 9, 2011
A comma is a way of putting a pause into a sentence. There are lots of places where commas are used, and they don't always have much to do with each other.
Lists of things
Items in a list are normally separated by commas. The last two items normally have an "and" between them.
The farm has pigs, horses, cows, and sheep.
Opinions differ on whether there should be a comma after the second last item, before the "and". In h2g2, we say there should be, but some publications leave it out. When writing for a site, journal or magazine, find out what the local house style says.
When using lots of adjectives
If a car is big and also red, then it is a big, red car. A string of adjectives before a nounare separated by commas, but there is no comma between the last adjective and the noun:
Little, green alien
Strong, bitter, black coffee
Sometimes the name of an item has an adjective built-in. A black widow spider is a type of spider. The "black" forms part of the name. You can't have any other sort of widow spider. So you treat "black widow spider" as if it were a noun. If you've got a small one, then it is a small black widow spider rather than a small, black widow spider.
When putting in an extra comment into a sentence
I was talking to the man, the one I mentioned earlier, and I told him about you.
In this case, there are two commas. You could remove the bit between the commas and the rest would still make a perfect sentence, so the bit between the commas is an aside. It adds extra information, but is not essential to understand the sentence.
Lists of things
Items in a list are normally separated by commas. The last two items normally have an "and" between them.
The farm has pigs, horses, cows, and sheep.
Opinions differ on whether there should be a comma after the second last item, before the "and". In h2g2, we say there should be, but some publications leave it out. When writing for a site, journal or magazine, find out what the local house style says.
When using lots of adjectives
If a car is big and also red, then it is a big, red car. A string of adjectives before a nounare separated by commas, but there is no comma between the last adjective and the noun:
Little, green alien
Strong, bitter, black coffee
Sometimes the name of an item has an adjective built-in. A black widow spider is a type of spider. The "black" forms part of the name. You can't have any other sort of widow spider. So you treat "black widow spider" as if it were a noun. If you've got a small one, then it is a small black widow spider rather than a small, black widow spider.
When putting in an extra comment into a sentence
I was talking to the man, the one I mentioned earlier, and I told him about you.
In this case, there are two commas. You could remove the bit between the commas and the rest would still make a perfect sentence, so the bit between the commas is an aside. It adds extra information, but is not essential to understand the sentence.
