Part xv. How to Properly Use Commas

                                    

                                          
This part was requested by _ChatBug_.
                          
What is a comma?

                          
While a period ends a sentence, a comma indicates a smaller break. Some writers think of a comma as a soft pause—a punctuation mark that separates words, clauses, or ideas within a sentence.
                          
Contrary to popular belief, commas don't just signify pauses in a sentence. Of all the punctuation marks in English, the comma is perhaps the most abused and misused. And it's no wonder. There are tons of rules about comma usage, and often the factors that determine whether you should use one are quite subtle. Unfortunately, I won't be able to cover all the rules here, but I will highlight what I deem are the most misused ways and the most important rules to remember.
                          
Do note that I have previously mentioned in this section some ways to use commas (i.e, comma splices, the oxford comma, etc.), so this part will not touch upon those rules, but they are still important to know and understand.
                          
Comma After Introductory Phrase
                          
A comma normally follows participial phrases that introduce a sentence:
                          
Correct: Grabbing her umbrella, Kate raced out of the house. Confused by her sister's sudden change in mood, Jill stayed quiet.
                          
When an adverbial phrase begins a sentence, it's often followed by a comma but it doesn't have to be, especially if it's short. As a rule of thumb, if the phrase is longer than about four words, use the comma. You can also use a comma with a shorter phrase when you want to emphasize it or add a pause for literary effect.
                          
Correct: After the show, Cleo will be signing autographs. Behind the building there is enough space to park two limousines. Without knowing why, I crossed the room and looked out the window. In 1816 life was very different. Suddenly, an angry black cat sprang from the shadows.
                          
But, if there is a chance of misreading the sentence, use the comma:
                          
Incorrect: Before eating the family said grace.
                          
Correct: Before eating, the family said grace.
                          
Commas with Interrupters or Parenthetical Elements
                          
Interrupters are little thoughts that pop up in the middle of a sentence to show emotion, tone, or emphasis. A parenthetical element is a phrase that adds extra information to the sentence but could be removed without changing the meaning of the sentence. Both interrupters and parenthetical elements should be set off with commas.
                          
Incorrect: The weather I was happy to see was beginning to clear.
                          
Correct: The weather, I was happy to see, was beginning to clear.
                          
Incorrect: Geoff's cooking skills if you can call them skills left something to be desired.
                          
Correct: Geoff's cooking skills, if you can call them skills, left something to be desired.
                          
Incorrect: It was sadly the last day of camp.
                          
Correct: It was, sadly, the last day of camp.
                          
Incorrect: Mary unlike Anne is very organized.
                          
Correct: Mary, unlike Anne, is very organized.
                          
Comma with a Question Tag
                          
A question tag is a short phrase or even a single word that is added to the end of a statement to turn it into a question. Writers often use question tags to encourage readers to agree with them. A question tag should be preceded by a comma.