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Common Punctuation Marks
Now that we’ve learned about different parts of speech, it’s time to learn about the rules of punctuation. These little marks can often cause heartaches and headaches, but the rules of punctuation are important to master because errors in punctuation can often result in unintended meanings. For example, consider the difference the comma makes in these two sentences:
Let’s eat, Grandpa.
Let’s eat Grandpa.
In the first instance, the writer is directly addressing his or her grandfather, and the comma indicates the separation between the suggestion being made and the addressee. In the second, however, the writer’s grandfather is on the menu.
When used correctly, punctuation helps guide readers through passages and clarifies how words and ideas relate to each other.(7)
End Punctuation
There are three punctuation marks that come at the end of a sentence: the period (.), the question mark (?), and the exclamation point (!). A sentence is always followed by a single space, no matter what the concluding punctuation is.
Periods
Periods indicate a neutral sentence (one that isn’t overly emotional or questioning anything), and as such they are by far the most common ending punctuation mark (they’ve been at the end of every sentence on this page so far). Periods occur at the end of statements.(8)
Question Marks
A question mark comes at the end of a question (“How was class today?”). Not all questions indicated by question marks are alike; for example, a rhetorical question (like “How could you do such a thing?”) is asked to make a point and does not expect an answer. Some questions are used principally as polite requests (“Would you pass the salt?”).
All of these questions can be categorized as direct questions, and all of these questions require a question mark at the end.(9)
Indirect Questions
Indirect questions do not have question marks at the end. They can be used in many of the same ways as direct questions, but they often emphasize knowledge or lack of knowledge:
- I can’t guess how Tamika managed it.
- I wonder whether I looked that bad.
- Cecil asked where the reports were.
Notice how different word order is used in direct and indirect questions; in direct questions the verb usually comes before the subject, while in indirect questions the verb appears second.(9)
Exclamation Points
The exclamation point is a punctuation mark usually used after an interjection or exclamation to indicate strong feelings or high volume. You’ve likely seen this punctuation mark overused on the Internet.
While you shouldn’t overuse exclamation points in academic or professional writing, there are appropriate ways and times to use them. A sentence ending in an exclamation point may be an exclamation (such as “Wow!” or “Boo!”), may state an imperative (“Stop!”), or may indicate astonishment (“They were the footprints of a gigantic duck!”).
The exclamation point is sometimes used in conjunction with the question mark. This can be in protest or astonishment (“Out of all places, the watering hole?!”). Such usage is discouraged in academic contexts.
Informally, exclamation points may be repeated for additional emphasis (“That’s great!!!”), but this practice is generally considered acceptable only in casual or informal writing, such as text messages or online communication with friends and family.(10)
Commas
Perhaps the most instructive way for us to approach the comma is to remember its fundamental function: it is a separator. Once you know this, the next step is to determine what sorts of things generally require separation. This list of things that should be separated includes most transition words, descriptive words or phrases, adjacent items, and complete ideas (complete ideas are word groups that contain both a subject and a verb). Commas are also used to separate similar items in lists.(11) (12)
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Other Comma Rules
Commas in Lists
Perhaps one of the most hotly contested comma rules is the case of the serial comma. The serial comma is the comma before the conjunction (and, or, and nor) in a series involving a parallel list of three or more things. For example, “I am industrious, resourceful, and loyal.” MLA (the style used in English classes) and APA style both require the use of the serial comma.
The serial comma can provide clarity in certain situations. For example, such a comma can help clarify a writer’s meaning if the and is part of a series of three or more phrases (groups of words) as opposed to single words:
Medical histories taken about each subject included smoking history, frequency of exercise, current height and weight, and recent weight gain.
Without the comma before the last and in this sentence (“, and recent weight gain.”), the list becomes clunky and hard to follow, especially since there is another and in the list (“current height and weight”).
The serial comma can also prevent the end of a series from appearing to be a parenthetical, which means a clarification of an idea that comes right before the comma. Consider the following confusing example:
I’d like to thank my sisters, Beyoncé and Rhianna.
Without the serial comma, it may appear that Beyoncé and Rhianna are the writer’s two sisters (which could be possible but isn’t true in this case). By adding the serial comma, it becomes clear that the speaker is thanking his or her sisters, as well as the two famous singers:
I’d like to thank my sisters, Beyoncé, and Rhianna.
Now each part of the list is clearly designated because it is set apart by a comma.
By always using a comma before the conjunction in any series of three or more, you honor the distinctions between each of the separated items, and you avoid any potential reader confusion.(11) (12)
Commas With Dates and Places
Commas separate the items in a date or place. For example:
- Jemal was born on March 5, 1985.
- On September 2, 2018, Melissa ate her last carb. (Note here that a comma goes after the year when the date does not come at the end of the sentence.)
- Bella lives in Beaumont, Texas.
- Earl calls Palatka, Florida, home.
Colons and Semicolons
Colons
Two other common punctuation marks in English are colons (:) and semicolons (;). They look similar, but they are used in very different ways.
Colons are often used to indicate the beginning of a list or to emphasize an explanation, definition, or clarification. Make sure that the word group that goes before the colon is a complete idea.
- When going on an afternoon hike, one should consider the following supplies: water, snacks, a compass, and a first aid kit.
- A good pro wrestler must have two above-average attributes: charisma and athleticism.
Semicolons
Semicolons are used to separate items in complex lists and to join complete ideas together.
When a list contains information that is set off by commas, it is easier to understand the list when a semicolon is placed between the items being listed.
- Ralph made a number of new hires, including Sarah, a design consultant; Mitch, a programmer; Lawshawna, a systems analyst; and Miles, a customer relations specialist.
- Joan has been to football games in Raleigh, North Carolina; Greenville, South Carolina; and Chattanooga, Tennessee.
When using a semicolon to join ideas together, you must make sure the word groups on each side of a semicolon can stand alone as a complete sentence. The content of the word groups should also be closely associated.
- Jeff hates rainy days; in fact, he will stay in bed until the afternoon during stormy weather.
- Melody would love to fight in the UFC; however, she doesn’t have time to train right now.
Apostrophes
Possession
The apostrophe is used in combination with an “s” to represent that a word literally or conceptually possesses what follows it. Singular words, whether or not they end in s, are made possessive by adding an apostrophe + s. For plural words, we typically indicate possession simply by adding the apostrophe without an additional s. However, when dealing with a plural form that does not end in an s (e.g., bacteria), we would add an apostrophe + s.
- a student’s paper
- one hour’s passing
- Illinois’s law
- interviewees’ answers
- her professors’ office (an office shared by two of her professors; if it were just one professor we would write her professor’s office)(11) (12)
For compound constructions like Mary and Jill or Ben and Mike, add the apostrophe + s to the last word in the grouping when ownership is shared:
- Mary and Jill’s house is two blocks away.
- Ben and Mike’s dog is nicely groomed.
If ownership is not shared, add the apostrophe + s to both words:
- Mary’s and Jill’s arms were broken in the fall. (Mary and Jill obviously “own” separate limbs.)
- Ben’s and Mike’s jobs were affected by the lockdown. (Here, Ben and Mike have separate jobs.)
Contractions
A contraction is a shortened phrase. He will becomes he’ll, are not becomes aren’t, would have becomes would’ve, and it is becomes it’s. In all of these cases, the apostrophe stands in for the missing letters.
You may find yourself being steered away from using contractions in your papers. While you should write to your teacher’s preference, keep in mind that leaving out contractions can often make your words sound overly formal and stilted. Also, you shouldn’t eliminate contractions in your papers just to up your word count!(11) (12)
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Quotation Marks
Quotation marks can be used in a number of ways. One way is fairly self-explanatory: you use quotation marks when you’re making a direct quote.
- He said, “I’ll never forget you.” It was the best moment of my life.
- Yogi Berra famously said, “A nickel ain’t worth a dime anymore.”
Note that you usually put a comma right before a direct quotation if you first write out who is speaking.
If you’re just writing an approximation of something a person said, you would not use quotation marks:
- She told me about Paulie, the three-toed sloth, yesterday.
- He said that he would be late today.
Another way to use quotation marks is to call attention to a word. For example:
- I can never say “Worcestershire” correctly.
- How do you spell “definitely”?
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Parentheses
Parentheses are most often used to identify material that acts as an aside (such as this brief comment) or to add incidental information.
Other punctuation marks used alongside parentheses need to take into account their context. If the parentheses enclose a full sentence beginning with a capital letter, then the end punctuation for the sentence falls inside the parentheses. For example:
Typically, suppliers specify air to cloth ratios of 6:1 or higher. (However, ratios of 4:1 should be used for applications involving silica or feldspathic minerals.)
On the other hand, if the parentheses indicate a citation at the end of a sentence, then the sentence’s end punctuation comes after the parentheses are closed:
In a study comparing three different building types, respirable dust concentrations were significantly lower in the open-structure building (Hugh et al., 2005).
Finally, if the parentheses appear in the midst of a sentence (as in this example), then any necessary punctuation (such as the comma that appeared just a few words ago) is delayed until the parentheses are closed.
You can also use parentheses to provide acronyms (or full names for acronyms). For example, “We use the MLA (Modern Language Association) style guide here” or “The Modern Language Association (MLA) style guide is my favorite to use.”
Remember, parentheses always appear in pairs. If you open a parenthesis, you need another to close it!(11) (12)
Ellipses
An ellipsis (plural ellipses) is a series of three periods.
As with most punctuation marks, there is some contention about its usage. The main point of contention is whether or not there should be a space between the periods (. . .) or not (…). MLA, APA, and Chicago, the three most common style guides for students, support having spaces between the periods. Others you may encounter, such as those guides used in journalism, may not.(13)
Quotes and Ellipses
You will primarily see ellipses used to indicate a missing portion in a quote. To understand this, let’s first look at the following passage:
Camarasaurus, with its more mechanically efficient skull, was capable of generating much stronger bite forces than Diplodocus. This suggests that Camarasaurus was capable of chomping through tougher plant material than Diplodocus, and was perhaps even capable of a greater degree of oral processing before digestion. This actually ties in nicely with previous hypotheses of different diets for each, which were based on apparent feeding heights and inferences made from wear marks on their fossilized teeth.
Diplodocus seems to have been well-adapted, despite its weaker skull, to a form of feeding known as branch stripping, where leaves are plucked from branches as the teeth are dragged along them. The increased flexibility of the neck of Diplodocus compared to other sauropods seems to support this too.
This is a lengthy quote, and it may contain more information than a writer who wants to include it in their work wants to use. Here’s how to cut it down:
Camarasaurus, with its more mechanically efficient skull, was capable of generating much stronger bite forces than Diplodocus. This suggests that Camarasaurus was capable of chomping through tougher plant material than Diplodocus . . . This actually ties in nicely with previous hypotheses of different diets for each, which were based on apparent feeding heights and inferences made from wear marks on their fossilized teeth.
Diplodocus seems to have been well-adapted . . . to a form of feeding known as branch stripping, where leaves are plucked from branches as the teeth are dragged along them.
In the block quote above, you can see that the first ellipsis appears to have four dots. (“This suggests that Camarasaurus was capable of chomping through tougher plant material than Diplodocus . . . ”) However, this is just a period followed by an ellipsis. This is because ellipses do not remove punctuation marks when the original punctuation is still in use; they are instead used in conjunction with original punctuation. This is true for all punctuation marks, including periods, commas, semi-colons, question marks, and exclamation points. For example, note the comma in the following sentence:
By looking at two sympatric species (those that lived together) from the fossil graveyards of the Late Jurassic of North America . . ., [David Button] tried to work out what the major dietary differences were between sauropod dinosaurs, based on their anatomy.
One of the best ways to check yourself is to take out the ellipsis. If the sentence or paragraph is still correctly punctuated, you’ve used the ellipsis correctly. (Just remember to put it back in!)(14)
Attributions
(7) Punctuation. Provided by: Lumen Learning. License: CC BY: Attribution 4.0
(8) Periods, Text: Punctuation Clusters. Authored by: Lumen Learning. License: CC BY: Attribution 4.0
(9) Question. Provided by: Wikipedia. License: CC BY-SA: Attribution-ShareAlike 3.0
(10) Exclamation mark. Provided by: Wikipedia. License: CC BY-SA: Attribution-ShareAlike 3.0
(11) Revision and Adaptation. Provided by: Lumen Learning. License: CC BY-NC-SA: Attribution-NonCommercial-ShareAlike 3.0
(12) Style For Students Online. Authored by: Joe Schall. Provided by: The Pennsylvania State University. Project: Penn State’s College of Earth and Mineral Sciences’ OER Initiative. License: CC BY-NC-SA: Attribution-NonCommercial-ShareAlike 3.0
(13) Ellipses. Provided by: Lumen Learning. License: CC BY: Attribution 4.0
(14) Modification of They might be giants, but how could they live with each other? Authored by: Jon Tennant. Provided by: European Geosciences Union. Project: Green Tea and Velociraptors. License: CC BY-NC-SA: Attribution-NonCommercial-ShareAlike 3.0
