Apostrophe
Use an apostrophe to indicate:
* The possessive case of singular and plural nouns, indefinite pronouns, and proper nouns:
my sister's son
somebody's lunch
my two sisters' sons
Charles's house
the children's toys the Rosses' friends
* The plural of letters, numbers, symbols, and words used as such:
too many thus's
ten 5's in a row
spelled with two e's
delete some &'s
* Missing letters in contractions and missing numbers in dates:
I'm (I am)
class of '95
ma'am (madam)
winter of '97–'98