A few basic rules for comma usage include the use of commas to separate independent clauses in a sentence and the use of commas after introductory clauses or phrases. Another basic rule is the use of commas after introductory adverbs that begin a sentence.
When two independent clauses in a sentence are joined by coordinating conjunctions such as "and," "but," "or," "so" or "yet", a comma must be used to separate the clauses. An example of this rule is as follows: "The birthday party was over, but the guests had not yet gone home."
Commas must also be used after introductory clauses, words or phrases that follow the main clause, such as in the following example: "If it stops raining this afternoon, we'll go to the park." Common starter words that indicate an introductory clause that must be followed by a comma include "while," "when," "since," "as" and "after."
A third basic rule for using commas requires using commas after an introductory adverb that starts a sentence. An adverb usually answers the question "how" and ends in the letters "-ly." An example of a comma used in this way is as follows: "Unsurprisingly, the man with no shoes burned his feet on the hot sidewalk."
Commas are usually used when separating items in a list and writing dates and addresses. Another rule for using a comma is to introduce or end a quote within a sentence. Commas are used in many different contexts and languages, and mean "something cut off or a short clause." Commas are written with the same shape as an apostrophe or as a single quotation mark.