Commas are used to indicate a pause between parts of a sentence, to separate items in a list, and to clarify meaning.

A comma should be used before 'and' in a list of three or more items to separate the last item from the rest.

I bought apples, oranges, and bananas.

Use a comma after an introductory phrase to separate it from the main clause, e.g., 'After dinner, we went for a walk.'

A non-restrictive clause provides additional information but is not essential to the meaning of the sentence and is set off by commas.

My brother, who lives in New York, is visiting us next week.

Use commas to separate the name of the person being addressed from the rest of the sentence, e.g., 'Can you help me, Sarah?'