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Run-On Sentences

Run-on sentences occur when writers try to combine more than one idea into a single sentence. They cause confusion because readers are not sure when one idea ends and the next one begins. Read our entry and test your knowledge with our quiz!


An apostrophe is a punctuation mark that makes a possessive form of a noun, which shows ownership. 


1. For singular nouns, an apostrophe is followed by “s” to indicate possession:

Example: The cat’s paws tracked dirt into the house.

In this sentence, the paws belong to the (singular) cat, so the correct form is “cat’s”.  Here are some additional examples

Example: The interior of Ron's car was ruined when he left the windows open during a storm

Example: I confess: I was starving so I ate Daryl's lunch.

Example: My ears were still ringing after attending Clancy's heavy-metal concert last night.

2. Singular nouns that end in “s” still follow the rule above:

Example: I borrowed one of Ross’s sweaters to wear to the play.

Even though “Ross” ends in “s”, “Ross” is singular and should follow the rule.  Here are further examples:

Example: JoJo took care of the class's hamster over winter break

Example: Trust me, you won't believe how long a walrus's tusks are until you see one in person.

Example: Belarus's main exports include heavy machinery and agricultural products.

3. To make a plural noun that ends in “s” possessive, simply add an apostrophe to the end:

Example: My parents’ house is very old.

In this sentence, the noun “parents” is plural and ends in “s”, so it needs to end in an apostrophe to be possessive.  Further examples:

Example: At the family reunion, all of the cousins' kids played together in back yard.

Example: Visiting the zoo, I couldn't help but be distracted by the animals' awful smell.

Example: The natives' hostility towards tourists is justified by the tourists' obnoxious behavior.

4. Do not use an apostrophe when you are simply using the plural form of a noun.

Incorrect: My cousin’s and I went to the zoo.

The cousins do not own anything in this sentence, so an apostrophe is not needed.   

Correct: My cousins and I went to the zoo.

Note: Apostrophes can be used to make contractions like can’t and don’t (shortened forms of can not and do not), but contractions should not be used in most forms of academic writing. Unless instructed otherwise, it is best to avoid contractions.