When I say comma, do you say cringe?

Punctuation is one of the most troubling aspects of writing. I’m not talking about your average period or question mark—it’s those pesky commas, colons, semicolons, and em dashes in the middle of a sentence that give us the jitters.

This resource is here to help.

, Commas ,

Let’s start with the most troublesome (and common) of them all: the comma.
Here are some rules:

1. Use a comma to separate a list of three or more items.
Ex. My favorite subjects are biology, history, and math.

2. Use a comma before the conjunctions for, and, nor, but, or, yet, so (acronym: FANBOYS) in a compound sentence.
Ex. I want to watch TV, but I have to do homework first.

Note: Don’t attach two independent clauses with a comma unless you have a conjunction!
WRONG I want to watch TV, I have to do homework first.
RIGHT I want to watch TV. I have to do homework first.
RIGHT I want to watch TV, but I have to do homework first.

3. Use a comma to separate two or more adjectives that can be interchanged.
Ex. It was a quiet, damp evening on campus. OR It was a damp, quiet evening on campus.

Note: Some adjectives are not interchangeable and don’t need a comma.
Ex. I can’t wait for a long spring break.
NOT I can’t wait for a spring long break.

4. Use a comma after a dependent clause, phrase, or introductory word at the beginning of the sentence.
Ex. If he were worried about his biochemistry test, he didn’t show it.
Ex. Hey, are you feeling better?

5. Use commas to separate unnecessary clauses or phrases in the middle of the sentence.
Ex. I go to Blue Angel, which is Phi Mu Alpha Sinfonia’s annual variety show, every year.

Note: Some descriptive clauses are necessary for clarity and should not be surrounded by commas.
WRONG The student, who cheated on the marketing test, was caught.
RIGHT The student who cheated on the marketing test was caught.

6. Use commas for dates and for separating cities from states. If placed in the middle of a sentence, commas go on both sides of the year or state.
Ex. April 27, 2018, is the scheduled day for Celebration of Scholarship.
Ex. Travelling from Miami, Florida, to Winona, Minnesota, in the middle of winter was not pleasant.

7. Use a comma before a quote with an introductory phrase (i.e., she said, the author wrote, he yelled, etc.).
Ex. When my stomach started grumbling, I said, “Let’s head to the Cardinal Club!”

That’s a lot of uses for a comma, huh? If you want even more rules, check out The online GrammarBook.

: Colons :

Now let’s move on to colons (not to be confused with semicolons).
Here are some rules:

1. Use a colon to start a list of items unless directly preceded by a verb that connects to the list.
WRONG My favorite classes are: Intro to Mass Communications, Sociological Imagination, and Global History to 1500.
RIGHT I am about to register for my favorite classes: Intro to Mass Communications, Sociological Imagination, and Global History to 1500.

Note: The list can be a single item.
Ex. One campus legend is more famous than any other: the ghost of Heffron Hall.

2. Use a colon to divide two independent clauses only if they are directly related to each other. Generally used for emphasis.
Ex. She finally achieved her goal: she made it into the Honors program.

Note: There is no clear consensus on whether to capitalize after using a colon in this way.

3. Use a colon to introduce a quote.
Ex. The business professor then told the students what they all wanted to hear: “The test will be delayed one week.”

Colons are great, but be careful. Colons and semicolons are not interchangeable. For more rules, check out the online GrammarBook.

; Semicolons ;

Combining a comma and period into one symbol, the semicolon creates a pause longer than a comma, but not as definitive as a period.
Here are some rules:

1. Use a semicolon to replace a period in order to connect two closely related sentences.
Ex. I loved taking disc golf as a PE class; I hope a racquet sport is just as fun.

Note: A period would not be incorrect in this usage, but it would create a harsher stop than a semicolon.

2. Use semicolons to divide elements of lists that already use commas.
Ex. I hope to study abroad in London, England; Rome, Italy; or Madrid, Spain, in the future.

3. Use a semicolon before words such as however, for example, specifically, or therefore when they start a complete sentence.
Ex. My roommate and I were in desperate need of a resupply; specifically, we were running out of snacks!

Try and mix in a semicolon or two the next time you write. Learn more at GrammarBook.

— Em Dash —

Em dashes are fun because they can replace other forms of punctuation.
Here are some rules:

1. Use an em dash to emphasize certain words or phrases in a sentence.
Ex. He could only think about one thing: dinner.
Ex. He could only think about one thing—dinner.
Ex. She ordered a lot of Cardinal coffee (at least three coffees a day).
Ex. She ordered a lot of Cardinal coffee—at least three coffees a day.

2. Use an em dash to signify an interruption in thought or speech.
Ex. I was happy—I should say ecstatic—to see that I aced the test.

Em dashes are great, but don’t overuse them. See the Punctuation Guide for more examples.

Choosing the Correct Punctuation

Even with these rules, you may struggle to decide which punctuation is correct. If you are struggling, here are a few key points.

1. A comma should never connect two independent clauses unless there is a conjunction (for, and, nor, but, or, yet, so). Leave that function to a semicolon or period.

2. Colons can start lists and quotes; semicolons cannot.

3. Colons divide independent clauses only if the second clause directly relates to the first. Semicolons are more lenient, so if you are unsure, it’s best to use a semicolon.

4. Use commas for quotes that are preceded or followed by phrases like “he said” or “she wrote.” Without these, either integrate the quote into your own grammar without punctuation or use a colon.

5. Em dashes can sometimes replace other punctuation to emphasize statements, but they should be used sparingly.


Now let’s practice! Check your answers at the end.

1. I love to play ____ ____ and volleyball at the RAC in my free time.
a. soccer, basketball,
b. soccer; basketball;

2. The Oldie Moldie All-Stars are ____ so I can’t wait to see them perform again.
a. fantastic,
b. fantastic;

3. I was walking over to Saint Yon’s ____ I guess I got lost.
a. Hall,
b. Hall;

4. When the going gets ____ the tough get going!
a. tough,
b. tough;
c. tough:

5. The Saint Mary’s Fitzgerald Library has plenty of the resources I ____ books, journal articles, and newspapers.
a. need,
b. need;
c. need:

6. I can’t wait to visit Berlin, ____ Warsaw, ____ and Vienna, Austria during my study abroad program.
a. Germany, Poland,
b. Germany; Poland;
c. Germany: Poland:

7. Punctuation is ____ but I know I can master it!
a. difficult,
b. difficult;
c. difficult:
d. difficult—


a, a, b, a, c, b, a