Use apostrophes to form standard contractions and indicate possession.
Note "it's" is "it is" and "its" indicates ownership by "it."
Do not use apostrophes to form plurals except for the following:
- Plurals of lowercase letters
- Plurals of abbreviations with interior periods
- Plurals of words where the word itself (noun or otherwise) is used as a noun of semantic interest (used "as a word")
Use straight apostrophes (') instead of curved apostrophes. This is easier to type and avoid errors.
Do
The dog's not on its leash (contraction of "dog is").
The dog's leash is green (leash belongs to the dog).
Mind your p's and q's (lowercase letter plurals).
There are so many Ph.D.'s in this room! (abbreviation with interior periods).
The results were five maybe's and two no's (words used as nouns).
It's nice outside (contraction of "it is").