The Period indicates the end of a sentence, of course, but it is also used to show termination of a number list, like, 1. The period ends abbreviations, like, e.g., i.e., Mrs., D.C., etc. Three periods (called an ellipsis) are used to express the omission of one or more words or sentences in a quotation. Ex. “I believe in everything…even if it’s in your mind…” John Lennon. Or if the omission occurs after the end of a sentence the three periods go after the period that ends the sentence.
The Question Mark indicates the end of question like Why? Did she say that? It can be used to mark uncertainty by putting parentheses. Ex. The cabin was built between 1870 (?) and 1875.
The Exclamation Point is used to express something strongly. Ex. Go sit down!
The Semicolon is used to express a pause. Ex. The shopper sat on the bench; she was waiting for her daughter. It can also separate large word groupings that have commas to avoid confusion.
The Colon indicates as follows. Ex. There are seven members: Sleepy, Doc, Bashful, Dopey, Sneezy, Happy and Grumpy. Sometimes used for drama. Ex. She only expected one thing: hatred. The colon generally will come behind as follows and would be put in place of the as a result. Ex. The owner filed bankruptcy: the store closed.
The Dash is two hyphens when typing and is used to express a break in the normal flow of a sentence. Ex. She asked–why on earth?–if she was his sister. It can also be used to separate parenthetical ideas or express afterthoughts.
The Hyphen makes compound words out of two or more words that are meant to be read as a single unit. Ex. She was a high-pressure interviewer. Use it also when adding a prefix. Ex. re-type. Use when writing out numbers like twenty-one or between year dates or game scores.
The Apostrophe marks where there are missing letters in contractions, plurals or to show possession. Ex. What’s up? Or 7’s, Emma’s shoe.
Parentheses enclose interruptions of sentence structure. Ex. It’s necessary (if you don’t want to get held up) to pay attention to the traffic reports. Numbers and letters can have parentheses around them to list multiples. Ex. The designs are labeled (a) modern, (b) contemporary.
Brackets are part of the parentheses family and are used by an editor for additions they made to quotations. Ex. “She [Eartha Kitt] played Cat Woman in the original series Batman.”
Quotation Marks indicates titles of short poems, chapter titles, magazine articles, short stories, essays and one-act plays. Most common, of course, is the direct quote and the period and comma always go inside the quotation in American writing. Ex. “It is hot outside.”
*Quotations within quotations are written with single quotations inside. Ex. “I’ve just finished writing my short story, ‘Whispers in the Hollow,'” I told Zane.
Colons and semicolons are always put outside of quotation marks. Other marks are put inside if they punctuate the quotation or outside if they punctuate the sentence of which the quotation is part.
*A new paragraph is started for each change in speaker in dialogue quotations.
Italics are used to show titles of motion pictures, novels, and books, full-length plays, and poems. They are used to show a word or letter independent of its meaning. Ex. The letter I should be capitalized when used by its self. Italics are also used to indicate emphasis and in novel writing to show thoughts or dreams.
The comma is before these words:
because they are coordinating conjunctions that will link two complete sentences known as independent clauses which have a subject and a verb.
Here’s an example: “I went shopping, and I washed the car.”
If you take out the word “I” in the second sentence which is the subject then, you wouldn’t need a comma because the second sentence no longer independently makes sense. Like this: “I went shopping and washed the car.” Washed the car cannot stand on its own because it’s missing the subject.
- Now, when a dependent clause starts a sentence, it’s like an introduction and needs a pause of a comma to make sense.
Here’s an example: “When I went shopping, I washed the car.”
This is a dependent clause because it has a subject and a verb, but “When I went shopping” cannot stand on its own.
- Appositives need commas to separate them to make sense in a sentence.
Here’s an example: “While shopping, I washed the car, a Mercury Grand Marquis.”
Appositives tell more about “the car.”
- Use commas to offset appositives from the rest of the sentence.
Appositives act as synonyms for a juxtaposed word or phrase. For example, “While running, I saw a mallard, a kind of duck.” “A kind of duck” is the appositive, which gives more information about “a mallard.”
If the appositive occurs in the middle of the sentence, both sides of the phrase need a comma. As in, “A mallard, a kind of duck, attacked me.”
Don’t let the length of an appositive scare you. As long as the phrase somehow gives more information about its predecessor, you usually need a comma.
“A mallard, the kind of duck I saw when I went running, attacked me.”
There’s one exception to this rule. Don’t offset a phrase that gives necessary information to the sentence. Usually, commas surround a non-essential clause or phrase. For example, “The duck that attacked me scared my friend” doesn’t require any commas. Even though the phrase “that attacked me” describes “the duck,” it provides essential information to the sentence. Otherwise, no one would know why the duck scared your friend. Clauses that begin with “that” are usually essential to the sentence and do not require commas.
- Use commas to separate items in a series.
For example, “I saw a duck, a magician, and a liquor store when I went running.”
That last comma, known as the serial comma, Oxford comma, or Harvard comma, causes serious controversy. Although many consider it unnecessary, others, including Business Insider, insist on its use to reduce ambiguity.
There’s an Internet meme that demonstrates its necessity perfectly. The sentence, “We invited the strippers, JFK, and Stalin,” means the speaker sent three separate invitations: one to some strippers, one to JFK, and one to Stalin. The version without the Oxford comma, however, takes on an entirely different meaning, potentially suggesting that only one invitation was sent — to two strippers named JFK and Stalin. Witness: “We invited the strippers, JFK and Stalin.”
- Use a comma after introductory adverbs.
“Finally, I went running.”
“Unsurprisingly, I saw a duck when I went running.”
Many adverbs end in “ly” and answer the question “how?” How did someone do something? How did something happen? Adverbs that don’t end in “ly,” such as “when” or “while,” usually introduce a dependent clause, which rule number two in this post already covered.
Also insert a comma when “however” starts a sentence, too. Phrases like “on the other hand” and “furthermore” also fall into this category.
Starting a sentence with “however,” however, is discouraged by many careful writers. A better method would be to use “however” within a sentence after the phrase you want to negate, as in the previous sentence.
- Use a comma when attributing quotes.
The rule for where the comma goes, however, depends on where attribution comes.
If attribution comes before the quote, place the comma outside the quotations marks. The runner said, “I saw a duck.”
If attribution comes after the quote, put the comma inside the quotation marks. “I saw a duck,” said the runner.
- Use a comma to separate each element in an address. Also, use a comma after a city-state combination within a sentence.
“I work at 257 Park Ave. South, New York, N.Y. 10010.”
“Cleveland, Ohio, is a great city.”
- Also use a comma to separate the elements in a full date (weekday, month and day, and year). Also, separate a combination of those elements from the rest of the sentence with commas.
“March 15, 2013, was a strange day.” Even if you add a weekday, keep the comma after “2013.”
“Friday, March 15, 2013, was a strange day.”
“Friday, March 15, was a strange day.”
You don’t need to add a comma when the sentence mentions only the month and year. “February 2018 went by fast.”
- Use a comma when the first word of the sentence is freestanding “yes” or “no.”
“Yes, I saw a loose dog when I went running.”
“No, the dog didn’t bite me.”
- Use a comma when directly addressing someone or something in a sentence.
“Anna, is that soup ready?”
Another clever meme shows the problem with the incorrect placement of this comma. “Stop clubbing baby seals” reads like an order to desist harming infant mammals of the seal variety. The version with a comma, however, instructs them to stop attending hip dance clubs. “Stop clubbing, baby seals.”
- Use a comma between two adjectives that modify the same noun.
For example: “I saw the big, mean dog when I went running.”
Only coordinate adjectives require a comma between them. Two adjectives are coordinate if you can answer yes to both of these questions: 1. Does the sentence continue to make sense if you reverse the order of the words? 2. Does the sentence still make sense if you insert “and” between the words?
Since “I saw the mean, big duck ” and “I saw the big and mean duck” both sound fine, you need the comma.
Sentences with non-coordinate adjectives, however, don’t require a comma. For example, “I lay under the powerful summer sun.” “Powerful” describes “summer sun” as a whole phrase. This often occurs with adjunct nouns, a phrase where a noun acts as an adjective describing another noun — like “chicken soup” or “dance club.”
- Use a comma to offset negation in a sentence.
For example: “I saw a dog, not a baby seal when I went running.”
In this case, you still need the comma if the negation occurs at the end of the sentence. “I saw a baby seal, not a dog.”
Also, use commas when any distinct shift occurs in the sentence or thought process. “The cloud looked like an animal, perhaps a baby seal.”
- Use commas before every sequence of three numbers when writing a number larger than 999. (Two exceptions are writing years and house numbers.)
For example, 10,000 or 1,304,687.
(Comma use source: Christina Sterbenz/Business Insider)