To make most nouns plural, add an -s or -es. The -es is added to words that end in an s or z sound.
Do not use an apostrophe.
Examples: lands dresses taxes quizzes
Incorrect: Twenty dog's were in the pack.
Correct: Twenty dogs were in the pack.
To make a plural noun possessive, simply add an apostrophe to the word. If the plural does not end in an s, then add an apostrophe plus s.
Examples: The girls' dresses
(The dresses belonging to the girls.)
The Wilsons' house
(The Wilsons live in the house.)
The men's room
(Plural does not end in s.)