- Use the apostrophe with contractions (can’t for cannot, don’t for do not, should’ve for should have). The apostrophe indicates the subtraction of letters.
- Use the apostrophe to show possession. Place the apostrophe before the s to show singular possession. (Jane’s hat, Mom’s car). NOTE: if the noun ends in s or an s sound, adding the extra s after the apostrophy is not required, but is preferred. However, if the word that follows the possessive also starts with s, do not add the second s.
- Use the apostrophe where the noun that should follow is implied. (This was ot his father’s, but his, jacket).
- To show plural possession, make the noun plural first. Then immediately use the apostrophe. (two boys’ hats, women’s hats, the actresses’ lines)
- DO NOT use an apostrophe for the plural of a name. (We visited the Smiths in Los Angeles).
- With a singular compound noun, show possession with ‘s at the end of the word (my mother-in-law’s birthday)
- If the compound noun is plural, form the plural first and then use the apostrophe to show possession (my two brothers–in-law’s birthdays).
- Use the apostrophe and s after the second name ony if two people possess the same item. (Jack and Jill’s home is very expensive). When separate ownership, use the s after both names (Cogburn’s and LaBoeuf’s military service record differs greatly).
- NEVER use an apostrophe with possessive prounouns: his, hers, its, theirs, ours, yours, whose. They already show possession so they do not require an apostrophe. (The book is hers, not theirs).
- The only time as apostrophe is used for it’s is when it is a contraction for it is or it has (It’s a nice day).
- The plurals for capital letters and numbers used as nouns are NOT formed with apostrophes. (“She consulted three M.D.s” or “She learned her ABCs from her grandmother”
Do use an apostrophe if that noun is plural. (“She went to three M.D.s’ offices” or the 1990s not the 1990’s, or the ’90s generation or the mid ’70s)
EXCEPTION: Use apostrophes with capital letters and numbers when the meaning would be unclear otherwise (“Please do not dot your i’s” or “Jack could not distinguish between 6’s and 0’s).
13. If the gerund has a pronoun in front of it, use the possessive form of that pronoun.
(“I appreciate your inviting me to dinner.” or “I appreciated his working with me to resolve the
DO NOT use an apostrophe to show a plural.