cables wrote:
One's first appearance
Rule 1.
Use the apostrophe with contractions. The apostrophe is always placed at the spot where the letter(s) has been removed.
Examples: don't, isn't, you're right, she's a great teacher.
Rule 2.
Use the apostrophe to show possession. Place the apostrophe before the s to show singular possession.
Examples: one boy's hat, Ms. Chang's house
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.
Examples: Mr. Jones's golf clubs, Texas's weather
Rule 3.
Use the apostrophe where the noun that should follow is implied.
Example: This was his father's, not his, jacket.
Rule 4.
To show plural possession, make the noun plural first. Then immediately use the apostrophe.
Examples: two boys' hats, the Joneses' golf clubs
Rule 5.
Do not use an apostrophe for the plural of a name.
Examples: We visited the Sanchezes in Los Angeles, the Changs have two cats and a dog.
Rule 6.
With a singular compound noun, show possession with 's at the end of the word.
Example: my mother-in-law's hat
Rule 7.
If the compound noun is plural, form the plural first and then use the apostrophe.
Example: my two brothers-in-law's hats
Rule 8.
Use the apostrophe and s after the second name only if two people possess the same item.
Example: Cesar and Maribel's home is constructed of redwood.
Rule 9.
Never use an apostrophe with possessive pronouns: his, hers, its, theirs, ours, yours, whose. They already show possession so they do not require an apostrophe.
Examples: (correct) This book is hers, not yours; (incorrect) This is your's.
Rule 10.
The only time an apostrophe is used for it's is when it is a contraction for it is or it has.
Examples: It's a nice day.
Rule 11.
The plurals for capital letters and numbers used as nouns are not formed with apostrophes.
Examples: She consulted with three M.D.s, the 1990s not the 1990's.
NOTE: She went to three M.D.s' offices (the apostrophe is needed here to show plural possessive).
Exception: Use apostrophes with capital letters and numbers when the meaning would be unclear otherwise.
Examples: Please dot your i's (you don't mean is).
Rule 12.
Use the possessive case in front of a gerund (-ing word).
Example: Alex's skating was a joy to behold.
Left hand, right hand, it doesn't matter. I'm amphibious.