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 show 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; add ‘ only for plural nouns that end in s)
    The men’s decision Three boys’ mothers
    The women’s success Four computers’ monitors
  3. To make compound words possessive, make the last word possessive
    My mother-on-law’s house caught on fire.
    The Department of Conservation’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: Penn and Teller’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 (Contraction: It is raining).
    We found its collar (Possessive: belonging to it [the dog]).
  6. 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 Chevy models are out.
    My daughter was born in ’00.