Learning when to use the comma, semi-colon, colon, ellipse, and em-dash. It's difficult for sure. I still don't have it down.
Today we will talk about the comma. I tend to overuse it. I often use it in places it doesn't belong, and don't use it in places in which is does.
The comma tells the reader to pause. Here are some guidelines about using the comma, which I gathered from Punctuation Made Simple.
1) Between Items in a Series
When you are listing three or more items in a sentence, simply place a comma between each member of the list. Here is an example:
Megan needs her computer, a notepad, a pen, a thumb drive, and a thesaurus in order to write a novel.
In that sentence it's pretty clear where the comma should be used. However, modern writers believe that the conjunction (and, but, or) does the same thing as a comma: it marks the place between two items in the set so it's not needed between the last and second to last items. As a result, you now have the option to choose whether to include the final comma. If your list is rather complex, however, omitting the comma may confuse the reader about where the second-to-last item leaves off and the last begins. In this case, of course, you would want to include the comma in order to avoid confusion.
2) Between Two Sentences
Many times a semicolon is used to connect two sentences. However, more often we glue two sentences together with a comma and conjunction (such as and or but). In fact, if you examine a document you have written recently, you are likely to find many such sentences; they’re so common that you don’t even realize you are writing them. When you do put two sentences together with a conjunction, you must also include a comma. That is, the conjunction and comma are equivalent to a semicolon when you’re connecting sentences. Here are three examples:
Megan has just finished her novel, and she has begun work on another novel.
The sentence above is made up of two sentences glued together with a comma and conjunction. For example, the first sentence is made up of the following:
Megan has just finished her novel.
She has begun work on another novel.
All you need remember is this: when you’re connecting two sentences with a conjunction, you must also include a comma because the conjunction and comma work together as a team.
Often you may use a conjunction but not have a complete sentence on both sides of it. In this case you do not need a comma. For example, you could easily rewrite the above sentences so that one part of each sentence is not a full sentence:
Megan has just finished her novel and has begun work on another novel.
Because in the above examples you do not have full sentences on both sites of the conjunction, there’s no need to include a comma.
One last bit of advice: if your sentence is very short (perhaps 5 to 10 words), you have the option of omitting the comma. Your reader can usually understand a short sentence more readily than a long one, and therefore you would not need a comma for readability.
3) To Attach Words to the Front or Back of Your Sentence
Most of the sentences we compose really consist of a short core sentence with many details added to that core sentence. Frequently, we add information to sentences by attaching one or more words to the front or back of the core sentence. You don’t need to memorize seven or eight rules naming each of the different structures you can add to your sentence. Instead, remember that when you add information to the front or back of a sentence, you will want to alert your want readers in order to help them clearly understand your message. Here are four examples:
In her bid for world domination, Megan spent every dime she had on a fully equipped laboratory.
Even when you add one word, such as certainly, at the beginning of a sentence, you want your reader to know where the real sentence begins. This is why you place the comma there.
4) On Both Sides of a Nonessential Component
Often, you will insert a group of words into the middle of a sentence. Sometimes this group of words will need to be set off by commas from the rest of the sentence, and sometimes you will not need commas. In order to tell whether you need commas, you must make a judgment about whether the added words are essential to the meaning of the sentence or whether they simply provide extra detail.
In order to tell a reader that a group of words is a nonessential component, you place commas in front and in back of the group of words. However, if omitting the group of words would drastically change the meaning of the sentence, then those words are not a component; rather, they are essential to the meaning of the sentence. In that case, you would not want to put commas on either side of the component so that the reader knows that those words are absolutely important to the meaning of the sentence. For example, look carefully at the following sentences:
Megan Bostic, who is a young adult author, will release her first novel in January.
Authors who write for young adults often explore teen issues.
In the first sentence, the information about me being a young adult author has no bearing on the main idea of the sentence: that I'm releasing my first novel in January.
The second sentence contains information that is absolutely essential to the meaning of the sentence: “who write for you adults.” If you were to place commas around these words, you would be telling the reader that the words constitute a nonessential component. For example, look at this sentence:
Authors, who write for young adults, often explore teen issues.
This sentence tells the reader that the main idea is that “authors often explore teen issues". Not all authors explore teen issues, but by enclosing the information in commas you have said that they do.
And thus ends my (and Punctuation Made Simple's) lesson about the comma. Come back next week for a lesson about the semi-colon.