Punctuation is one of the key parts of good writing. It's how you organize your words so that they make sense for the audience - without all those dots and dashes, everything your write in your paper would just be a jumble. That's why bad punctuation can be so disastrous for your paper. A comma or colon in the wrong place can change the whole meaning of a sentence, so take the time to learn how to punctuate correctly to create high-quality academic papers
Periods are the dots that end sentences. They signal the conclusion of a complete thought, meaning that anything you end with a period should be a complete sentence with a subject and verb. When you're reading you take a pause at each period, and when you're reading out loud this is frequently where you'd stop to take a breath.
Traditionally, periods were followed by two spaces, but with the advent of computer word processing programs it's become common to just use just one space between sentences. Either is acceptable as long as it's uniform throughout the paper. Periods have a number of other uses as well, for example in abbreviations (Mrs. Walker) and website addresses (www.google.com).
While periods are pretty straightforward, commas are among the more problematic punctuation marks for many students. Generally, commas are used to separate words, phrases, or clauses so that they are not directly linking to the words around them. When reading, a comma is a shorter pause than a period - you're not starting a new idea, just breaking up distinct ideas within a sentence.
Series. Commas are used to separate items in a list.
Don't forget to pack your hat, coat, mittens, and scarf.
Sometimes the comma before the conjunction (known as the Oxford or serial comma) is left out. Either is correct, so it's up to you and the style guide you're using which you choose.
We'll need eggs, milk, flour and butter for the cake.
If leaving out the comma creates ambiguity in the sentence, it's best to leave it in.
I'd like to thank my parents, Alice Smith and Mark Watt.
In the above example, it's not clear whether four separate people are being thanked (my parents along with Alice Smith and Mark Watt) or whether Alice Smith and Mark Watt are my parents. Adding the serial comma removes the ambiguity.
I'd like to thank my parents, Alice Smith, and Mark Watt.
Clauses. Another common use for commas is to separate clauses in a sentence. When there are two independent clauses (clauses that can stand alone as their own sentences), they are joined by a comma and a conjunction (and, but, or, etc.). [Note: when two independent clauses are joined by a comma without the necessary conjunction it's an error known as a comma splice.]
We're going to drive to the store, but first you need to take the dog for a walk.
Commas also separate an independent clause and a dependent clause (a clause that can't stand alone as its own sentence) if the dependent clause comes first.
If you're leaving, please close the door on your way out.
In the above example, "if you're leaving" is the dependent clause, while "please close the door on your way out" is independent.
When the independent clause comes first, no comma is needed.
She wants start work immediately but isn't sure where to start.
Phrases. An appositive is a phrase that describes the preceding noun in the sentence. It's set off by commas.
Her husband, a teacher at the local middle school, might be able to help.
Other phrases, like interjections and aside, are also set off my commas.
The answer, if you'd really like to know, is in the back of the book.
Oh my gosh, I can't believe she said that.
Adjectives. If you're using more than one distinct adjective in a row, they should be separated by commas.
The big, green, shiny apple was sitting right there on the desk.
Adverbs. Certain adverbs, including still, therefore, moreover, and in fact need to be set off by commas.
In fact, we're going to be leaving right after the show ends.
With other adverbs, including so, too, and then, the comma is optional.
I'm going to the party, too.
I'm going to the party too.
Like commas, semicolons are used to separate words and phrases within a sentence. They're slightly more forceful than a comma - when reading they indicate a longer pause.
Lists. Semicolons are used instead of commas to separate items in a list when those items already contain internal commas.
At the office I saw Jim, the secretary; Alice, who works in the stock room; and my boss Carol.
Clauses. Semicolons are also used to separate two independent clauses that are joined without a conjunction or with a transitional phrase like however or of course.
The party is at eight; we should be able to have dinner first.
We'll be late; however, I called ahead to let them know.
Colons are used to introduce a word or phrase - think of it as saying "for example" or "here it is".
Parts of a set. Use a colon before a list that explicitly states the parts of a set identified earlier in the sentence.
I have four classes tomorrow: calculus, biology, statistics, and history.
Don't use a colon before a list if you aren't clarifying the contents or particulars of something you've already mentioned. For example,
She packed: two shirts, a skirt, and an extra pair of shoes.
is incorrect. It can be rewritten in several ways.
She packed two shirts, a skirt, and an extra pair of shoes.
She packed all of her clothes in a suitcase: two shirts, a skirt, and an extra pair of shoes.
Consequences. Colons can also introduce a consequence of the preceding sentence.
There was only one possible explanation: her phone was turned off.
Question marks (?)
Like the name suggests, a question mark is used at the end of the sentence to indicate that you're asking a question.
Exclamation point (!)
The exclamation point is used at the end of sentences to indicate shouting or strong feelings.
I can't believe you did that!
Quotation marks (" ")
Quotation marks go around phrases that are direct quotes from speech or written sources.
She said, "I think we should just be friends".
In his book on Shakespeare, the scholar Walter Minks names Hamlet as Shakespeare's best play: "Without a doubt, Shakespeare is best known for the unstable prince at the center of Hamlet."
Punctuation at the end of sentences can go either inside or outside the quotations, depending on the style guide you're using.
The expert said that "we shouldn't be concerned".
The expert said that "we shouldn't be concerned."
Below is a classic example of just how important punctuation can be.
I want a man who knows what love is all about. You are generous, kind, thoughtful. People who are not like you admit to being useless and inferior. You have ruined me for other men. I yearn for you. I have no feelings whatsoever when we're apart. I can be forever happy - will you let me be yours?
Move a few commas and periods around, and you get something completely different:
I want a man who knows what love is. All about you are generous, kind, thoughtful people, who are not like you. Admit to being useless and inferior. You have ruined me. For other men, I yearn. For you, I have no feelings whatsoever. When we're apart, I can be forever happy. Will you let me be?