Commas are the most frequently confused mark of punctuation. Writers must decide when to use them and when NOT to use them. It is not always an easy task. In simple form, commas should be used in six basic ways. Commas should be used to set off introductory words, phrases, and clauses. Anything that is written BEFORE the main clause (a complete sentence) should be followed with a comma. Common introductory words that should have a comma after them are: yes, no, well, however, and see. For example: Yes, I will go to the meeting with you. Common words that begin introductory phrases are: while, before, if, because, after, when, and since. For example: When it was time to go home, I did not want to leave. Commas are also used to join items in a series of three or more. While it is sometimes debated whether the last comma (after and) is necessary, it is better to include it. For example: I went to the store and purchased an umbrella, a raincoat, and rain boots. Commas are one way to join independent clauses. Independent clauses joined by a coordinating conjunction need a comma.
Coordinating conjunctions are: for, and, nor, but, or, yet, so. For example: John and Malinda are engaged, and they are planning an elaborate party. Use a pair of commas around “interrupters” that appear as words, phrases or clauses in the middle of a sentence that are not essential to the meaning of the sentence. For example: Mr. Higgins, my English instructor, is up for tenure. “My English instructor” simply provides clarification or additional information, but does not change the meaning of the sentence. With direct quotations, a comma should be used prior to the quote if the sentence does not start with the quote. For example: Heather said, “Did you see that?”. If the quote is broken, a pair of commas should surround the interrupter. For example: “I saw Jason,” Heather said, “and he was looking fabulous.” Finally, commas should be properly placed in names and dates. Commas should come between cities and states, as in Austin, Texas. Commas should separate the date and year in a written date. For example: September 11, 2001. Commas should also appear in a person’s name if she or he has a title. For example: Dale Earnhardt, Jr. or Katherine Bently, MD. Following comma rules is not always easy. Learning where commas are placed is essential to good grammar.