Use an apostrophe (')

1. To form possessives of nouns:

   
   Singular: add 's: John's, a girl's

   Plural: add s': boys' coats, girls' dresses

   But: when a word is already plural by form, just add 's:

   women's, men's, children's, people's
   
   

2. To indicate missing letters:

   
   In contractions: I'll, won't, let's, doesn't, it's (it is)

   In dialect or conversation: He's goin' to be singin'.
   
   

3. With single letters, numbers, and words to form plurals:

   
   Mind your p's and q's.

   There are too many if's in your plan.

   His card was misfiled in the b's.

   There are four s's in Mississippi, four i's, and two p's.

   Your 7's look like l's.
   
   

4. In abbreviated years:

   
   Class of '96