8-13 Rules to Use Apostrophe
From "The Spellbrainer"
Use the Apostrophe with contractions. The Apostrophe is always placed at
the spot where the letter(s) have been removed. Examples : don't, isn't,
you're are right.
Use the Apostrophe to show possession. Place the Apostrophe before the s to show
singular possession. Examples : one boy's hat, one woman's hat, one child's hat.
Note : Although names ending in s or an s sound are not required to have the second
s added in possessive form, it is preferred. Texas' weather, Straus's daughter.
Use the apostrophe where the noun that should follow is implied. Example :
This was his father's, not his jacket
To show plural possession, make the noun plural first. Then use the
apostrophe immediately. Examples : two boys' hats.
Do not use the apostrophe for the plural of a name. Example : The Mishras
have two cats and a dog.
With singular compound noun, show possession with s at the end of the
word. Example : my mother-in-law's hat,
If the compound noun is plural, form the plural first and then use the
apostrophe. Example : my two brothers-in-law's hats
Use the apostrophe and s after the second name only, if two people possess
the same item. Example ; Ram and Krishna's home is far away. Ram and
Krishna's contracts will be renewed next year. indicates separate
Never use an apostrophe with possessive pronouns : hers, yours, his, its,
theirs, ours, whose. They already show possession so they do not an apostrophe.
Example : This book is hers, not yours.
The only time an apostrophe is used for it's is when it is for a contraction for
"it is" or "it has". Example ; It's a nice day. It's your
right to refuse. It's has been great to know you.
The plurals for capital letters and numbers used as nouns are not formed
with apostrophes. Example : She consulted with three MDs but she went to
three M.D's offices. The apostrophe is needed here to show plural possessive.
She learnt her ABC's, 1990s are not the 1990's. She learned her time tables
for 6s and 7s.
Exception : use apostrophe with capital letters and numbers when the
meaning would be unclear otherwise. Example : Pleas dot your i's, Sita
could not distinguish between her 6's and 0's.
Use the possessive case in front of gerund (-ing word). Example : Rita's
skating was a joy to behold. This does not stop principal's inspecting of
If the gerund has a pronoun in front of it, use the possessive form of
that pronoun. Example : I appreciate your inviting me to dinner, I
appreciated his working with me