1. Use the apostrophe in contractions. Place the apostrophe where the omitted letter(s) was.
does not it is I am I have We are
doesn't it's I’m I've We’re
2. Use the apostrophe to indicate ownership.
Singular nouns and indefinite pronouns: (Add 's)
the boy's mother the event's cause Jesus's disciples
Larry's house everybody's problem Dickens's novels
Plural nouns: (Add 's for plural nouns that do not end in -s)
the men's decision
the women's success
(Add ' for plural nouns that end in -s)
three boys' mothers
four computers' monitors
3. To make compound words possessive, make the last word possessive.
My mother-in-law's house caught on fire.
The Department of the Interior's policies usually work.
4. To make two or more nouns possessive, make the last noun possessive if it is considered one
unit. If they are separate units, make both nouns possessive.
SINGLE UNIT: Martin and Lewis's act broke up.
SEPARATE UNITS: I like Trigger's and Champion's saddles.
5. Do not use an apostrophe with possessive pronouns.
This is hers.
The dog hurt its foot.
Be sure to distinguish between ITS and IT'S.
It's raining. (It is raining.)
We found its collar. (belonging to it [the dog])
4. Use apostrophes to indicate years when the first two numbers of the current century are
omitted (or when the century is clearly understood). The '02 models are out.
My daughter was born in '00.
5. Use apostrophes to form the plurals of numbers, letters, symbols, and words used as terms.
The 9's in this set of numbers are all broken.
Mind your p's and q's.
Two P.O.W.'s were released.
Not everyone believes in UFOs. (No apostrophe needed here)