"He hit the ball, dropped the bat, and ran to first base."
You may have learned that the comma before the "and" is unnecessary, which is fine if you're in control of things. However, using a comma between all the items in a series, including the last two, avoids gobbed words..
For example, "He hit the ball well, but he ran toward third base." Contending that the coordinating conjunction is adequate separation, some writers will leave out the comma in a sentence with short, balanced independent clauses (such as we see in the example just given). If there is ever any doubt, however, use the comma, as it is always correct in this situation.
For example, "Running toward third base, he suddenly realized how stupid he looked."
It is permissible to omit the comma after a brief introductory element if the omission does not result in confusion or hesitancy in reading. If there is ever any doubt, use the comma, as it is always correct. If you would like some additional guidelines on using a comma after introductory elements, click HERE.
For example, "The Founders Bridge, which spans the Connecticut River, is falling down."
By "parenthetical element," we mean a part of a sentence that can be removed without changing the essential meaning of that sentence. Appositives are almost always treated as parenthetical elements.
An absolute phrase is always treated as a parenthetical element, as is an interjection. An addressed person's name is also always parenthetical. Be sure, however, that the name is that of someone actually being spoken to. A separate section on Vocatives, the various forms that a parenthetical element related to an addressed person's name can take, is also available.
- Their years of training now forgotten, the soldiers broke ranks.
- Yes, it is always a matter, of course, of preparation and attitude.
- I'm telling you, Juanita, I couldn't be more surprised. (I told Juanita I couldn't be more surprised. [no commas])
You could think of this as "That tall, distinguished, good looking fellow" rule (as opposed to "the little old lady"). If you can put an and or a but between the adjectives, a comma will probably belong there.
Be careful not to use commas to set off quoted elements introduced by the word that or quoted elements that are embedded in a larger structure:
Use Commas With Caution
As you can see, there are many reasons for using commas, and we haven't listed them all. Yet the biggest problem that most students have with commas is their overuse. Some essays look as though the student loaded a shotgun with commas and blasted away. Remember, too, that a pause in reading is not always a reliable reason to use a comma. Try not to use a comma unless you can apply a specific rule from this page to do so. Concentrating on the proper use of commas is not mere form for form's sake. Indeed, it causes writers to review their understanding of structure and to consider carefully how their sentences are crafted.