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Self Teaching Unit:


©  2000, 1978 Margaret L. Benner

An apostrophe is a small punctuation mark () placed after a noun to show that the noun owns something.


The apostrophe will always be placed either before or after an s at the end of the noun owner.


Always the noun owner will be followed (usually immediately) by the thing it owns.


How can you know:

1.      when to use an apostrophe


2.      where to place the apostrophe CORRECTLY?


 First, determine which noun is the owner:

a cow’s nose

            To qualify for apostrophe use, the owner:

1.      must be a noun (cow)

2.      must be positioned in front of the thing it owns


That’s all there is to it!

            a cow’s nose means a cow owns a nose


Link to Exercise 1


Now you know when and how to make a singular noun show possession with an apostrophe.

The rules for apostrophe use with a plural noun owner are just a little more complicated.

Follow these steps.

  2.      If the noun owner is plural (more than one owner), do these two things.

  1. Place an apostrophe at the end of the noun owner.
  1. Check to see whether the plural noun already ends in s.

                 four cows noses             (yes, it does)

If the plural noun DOES end in s (as most English plural nouns do), do NOT add another s.  You have already formed the plural possessive.

            four cows’ noses

Here are some examples of plural possessive nouns.  Notice how each follows the rules for apostrophe placement.


Link to Exercise 2


The exception to the plural possessive rule . . .

A few plural nouns do not end in s.  Instead, these nouns form their plural with an internal change.


To form the possessive of such plural nouns, follow these steps.

For our example, we will use this sentence:


Now the plural possessive is formed correctly.


Correct possessive form for plural noun owners that end in s:


Correct possessive form for plural noun owners that do not end in s:



Link to Exercise 3



You have learned that nouns form their possessive by adding apostrophes.  Some pronouns form their possessive in the same way as singular possessive nouns.


However, one group of pronouns does NOT add an apostrophe to form the possessive.  This group is the personal pronouns.


Most of these personal pronouns offer no problem.

*Only its gives many people trouble.

            Some writers mistakenly write it’s to indicate the possessive form of it.


                      THIS IS AN ERROR!


It’s is ALWAYS a contraction for it is or it has.


Its (NO apostrophe) is the possessive form of it.


Link to Exercise 4

Link to the POST TEST

For further information on these resources, contact
Margaret L. Benner

copyright  ©2011 Towson University, Writing Support Program. All rights reserved.