Punctuation Standards

Punctuation Rules Examples
Put a period at the end of a sentence.

Maybe I should clarify: periods go at the ends of declarative sentences (i.e., those that are not questions).
This is a sentence. So is this. Notice how I end them all with periods. You should do the same.
Put a question mark at the end of a question.

Questions are called interrogative sentences.
Is this rule that hard to understand?
Do you know the difference between a declarative and an interrogative sentence?
Put periods after abbreviations and initials.
Mr. Johnson is a friendly guy.

I saw Dr. Smith on Wed., Jan. 4.

Use commas in dates.

Notice that when you write a date within a sentence, commas must separate not only the day from the year, but also the year from anything that follows it.

I was born on February 29, 1960, and my sister was born on November 20, 1963.

Use commas in addresses as well as in the greeting and closing of a letter.

San Francisco, California

Dear Mary,


Put commas after words in a series.
A series means three or more items.

Although most newspapers and magazines do not, you should put a comma before the and that comes before the final item. Commas can also separate phrases and clauses that are in a series.

Skip ate a hot dog, a hamburger, and a banana split.

Last summer I swam, jogged, bicycled, and lifted weights.

When setting up your computer, make sure you find a suitable spot that is dry, connect all the cables properly, and plug in all the components.

Put commas after introductory words.

Well, I’ve never been so insulted in all my life!

Again, I must warn you against this stunt.

Looking around the kitchen, I spied the pizza.

Put commas before, after, or around the attribution in a direct quotation.

“You must capitalize,” the teacher said, “the first word in a direct quote.”

The students asked, “Even if it’s a fragment?”

“Yes,” the teacher replied.

Put quotation marks around direct quotations.

Most of the time, other punctuation marks belong inside the quotation marks.

I said, “Look at the box above this one for more examples of how to use quotation marks.”

Put an exclamation mark after a word or phrase expressing strong emotion.

The exclamation mark is overused. Many students think lots of exclamation marks make writing stronger. They don’t! And, don’t ever put more than one exclamation mark at the end of a sentence!

“Ow!” he shouted when the doctor gave him a shot.

“Stop it!” she yelled.

“Fire! Everybody out!”

Use apostrophes to show possession.

The apostrophe is the most misunderstood punctuation mark. Many people think it is used to show plurals. It is not! Also, the great exception to the possession rule is the word it’s, which, when spelled with an apostrophe, means it is. Its (without an apostrophe) is the possessive form of the word.

Mary’s car is in the driveway.

James’s money is on the table.

That is the Thompsons’ house. (The apostrphe comes after the s when making plural words possessive.)

Use apostrophes to show contractions.

Contractions are words that are abbreviated by removing some of the letters. The apostrophe indicates those missing letters.

I won’t do this. (will not)

She couldn’t see me. (could not)

He’s over there. (He is)

Use a comma after an introductory clause and before conjunction in a compound sentence.

A clause is a group of words that contains a subject and a verb. Many clauses are complete sentences. A conjunction is a word that joins parts of a sentence (and, but, or, etc.). A compound sentence is created when the information from two sentences is combined into one.

If you have two complete sentences that could stand on their own, and you combine them with a conjunction, you have to put a comma before the conjunction.

Although I am a teacher, all my friends are medical professionals.

Those girls are playing with fire, and they are going to get burned.

I have to check all the locks before bed, or I don’t feel secure at night.

This rule is fairly simple, but many students don’t apply it in their writing.

Use a semicolon between two main clauses not joined by a conjunction.

A semicolon is used sort of like a period; they both indicate a separation between complete ideas. When the content or idea of two complete sentences is closely related, you may choose to separate them with a semicolon instead of a period. If you do, however, be sure not to also use a conjunction.

I am a teacher; all my friends are accountants.

Those girls are playing with fire; they will get burned.

Semicolons are simple; more students should use them.

Use a colon to introdcue a list.

The colon is often misused because people think that whenever you list things you have to use a colon. This is not true. A colon never follows a verb, and it should be preceded by a complete sentence.

Please complete the following tasks: clean the garage, empty the garbage, and scrub the floor.

Sandy wanted many things: a new car, a bigger house, a boat, and a pet lizard.

Last summer I swam, jogged, biked, and danced every day. (No colon needed.)

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