Comma – Punctuation mark
Commas reflect pauses in speech.
A listing comma is used to separate items in a series or list. In British English, the last two items in a list are not usually separated by a comma unless these are long.
- The Three Musketeers were Athos, Porthos and Aramis.
- I went to China, Japan, Malaysia and Singapore.
A joining comma is used to join two complete sentences into a single sentence. It is usually followed by a connecting word like and, or, but, while or yet.
- We can go swimming, or we could stay here.
- I decided to come home earlier than I had planned, and the others spent the evening at the local disco.
A gapping comma is used to show that certain words have been omitted instead of repeated.
- Jane decided to order the home-made steak pie and Alice, the duck special. (The omitted words are decided to order.)
When subordinate clauses begin sentences, they are often separated by commas.
- After I left school, I went to London.
If words or expressions interrupt the normal progression of a sentence, we usually separate them off by commas.
- John, however, did not turn up.
- We were, believe it or not, in love with each other.
We use commas to mark off a noun or phrase in apposition.
- Milton, the great English poet, was blind.
- Paul, the apostle, was beheaded during the reign of Nero.
Commas are used to mark off a participial phrase from the rest of the sentence.
- Driven by rain, we took shelter under a tree.
- Caesar, having conquered his enemies, returned to Rome.
A non-defining relative clause is separated from the rest of the sentence by commas.
- Sailors, who are generally superstitious, say it is unlucky to embark on a Friday.