Read this section to learn about apostrophes, another important and multi-purpose punctuation. What you read here will connect to ideas you'll read about in the next section about confused words.
Possessive Case
Using apostrophes to show possession with singular nouns:
A. To form the possessive of singular nouns that DO NOT end with the letter S, add 's:
Jim's nose
my sister's thesis
Helen's teeth
the student's desk
The cat's food
Shakespeare's sonnets
The possession or ownership in these examples is explicit. Sometimes, however, ownership is loosely implied, as in the following examples:
a day's work
a tree's roots
the diet's benefits
winter's chill
If you're uncertain whether a noun is possessive, try rewriting the phrase as an "of" phrase:
the work of the day
the roots of a tree
the benefits of the diet
the chill of winter
B. To form the possessive of singular nouns that DO end with the letter S, just add an apostrophe.
In the following, the extra S sound is easy to pronounce, so add 's:
Queen Bess' throne
Lois' sister
my boss' office
Charles Dickens' novels
Holmes' pipe
Sophocles' plays
for goodness' sake (for the sake of goodness)
Using apostrophes to show possession with plural nouns:
A. To form the possessive of plural nouns that DO NOT end with the letter S, add 's:
women's rights
men's room
children's games
B. To form the possessive of plural nouns that DO end with S, add only an apostrophe:
girls' basketball team
the lawyers' briefcases
three days' pay
in twelve months' time
the wrens' nests
the bosses' secretaries
Note: Don't be confused by the plural form of names ending in S, like Jones or James. When Mr. and Mrs. Jones and all their children walk around together, they are "the Joneses". To form the joint possessive, add an apostrophe only :
"We were invited to the Joneses' house."
C. To show joint possession, use 's(ors') with the last noun only:
Fernando and Eva's wedding
The same rule applies to compound words:
my mother-in-law's garden
the president-elect's vocabulary
the secretary-of-state's speech
her in-laws' vacation
Possessive Pronouns
"Hers", "his", "ours", "yours", "theirs", "whose", AND "its" have no apostrophe:
The cat lost its tongue.
His singing is beautiful.
One of the most common apostrophe errors occurs with "its" and "it's". Just remember that "its" is a possessive pronoun, just like "his" and "her", and like them, DOES NOT have an apostrophe. "It's", however, is a contraction for "it is" and "it has".
The cat knows its name; it's called Pasha.
Finally, keep in mind that the use of the apostrophe is not the only way or always the best way to indicate possession. Instead of "an hour's pay", for example, you may write "hourly pay". Choose the form that is the most precise or the most appropriate.