The comma is used to indicate a pause between parts of a sentence.
Uses of the comma
Before and after words used in apposition to a noun
- Winston Churchill, the statesman, was also an eminent writer.
Janaki, my sister, is an eminent cardiologist.
To separate two or more nouns, adjectives, or adverbs that come together
- England, Russia and France formed an alliance.
To separate a participial phrase
- Feeling tired, I went to bed.
- Being fat, she couldn’t run fast.
To mark off a noun
- James, can we bank on him?
- Mary, have your meals.
- John, come here.
After an introductory phrase or clause
- To be honest, I have little interest in politics.
- For God’s sake, leave me alone.
- In the name of justice, be fair to that poor man.
To indicate the omission of a verb in cases where repetition should be avoided
- My brother bought a watch and my sister, a camera. (= My brother bought a watch and my sister bought a camera.)
Before and after words or phrases let into the body of a sentence
- She had, surprisingly, paid for everything.
- The boy had, in spite of all the hardships he faced, managed to succeed.
To separate a subordinate clause from the main clause
- After he had finished his job, he went out.
- When I opened the door, the cat jumped in.
The comma can be omitted when the subordinate clause goes after the main clause.
