Apostrophes

*Strategy: Since we don’t “hear” apostrophes in spoken English, they are easy to leave out in writing. If you have trouble remembering apostrophes, here is a crude but effective proofreading technique: stop at every word in your draft that ends with s and ask yourself, “Is this a possessive?” (Does the next word belong to this s-ending word?) If you do this faithfully, eventually you will learn to ask yourself as you write.

For singular possessives, add 's to the singular form.

the cat’s fur (one cat)

the mouse’s tail

Jane’s roommate

When a singular noun already ends in s. you still add ‘s for the possessive in most cases because you are adding a new syllable.

Chris (one syllable)

Chris’s (two syllable) book

Linus (two syllables)

Linus’s (three syllables) blanket

When no new syllable is added in the possessive form of a singular word ending in s, just add an apostrophe.

Massachusetts (four syllables)

Massachusetts’ (still four syllables) laws

For plural possessives, add an apostrophe after the final s. For irregular plurals (not ending in s), add ‘s.

the cat’s fur (more than one cat)

the mice’s tails