The apostrophe, a flying polliwog of punctuation, often challenges writers. It functions to show possession and becomes a place saver in other situations. It does not form plurals.
Rule 1: To form the possessive of a singular noun that does not end in s or an s sound, add an apostrophe plus s to the noun:
Examples: the writer's pen, John’s pencil, my friend’s book
Rule 2: To form the possessive of a singular noun that does end in s or an s sound, add an apostrophe plus s to the noun:
Examples: James's report, a witness's answer, Jennifer Lopez's song.
Examples: Sophocles' plays, Mary Rogers' bouquet
Rule 3: To form the possessive of a plural noun that ends in s or es, add only an apostrophe to the noun:
Examples: the teachers' books, the writers' lessons, their friends' papers, the beaches' shells.
Rule 4: To form the possessive of a plural noun that does not end in s or es, add an apostrophe plus s to the noun:
Examples: children's toys, the women's dressing room
Rule 5: To indicate separate possession, add whichever possessive sign is appropriate (an apostrophe plus s or an apostrophe alone) to the name of each person:
Examples: Bill's and Tom's cars (two separate cars: Bill's car and Tom's car), James's and Olivia's houses (two separate houses: James's house and Olivia's house)
Rule 6: To indicate joint possession, add the appropriate possessive sign (an apostrophe plus s or an apostrophe alone) to the final name:
Examples: Mary and John's house (the house belongs to both Mary and John). Edward and Madeleine's books (the books belong to both Edward and Madeleine).
Example: Erica's and my project (not Erica and my project); Mark's and our dinner (not Mark and our dinner); John's, Edgar's, Lisa's, and my party (not John, Edgar, Lisa, and my party)
Possessive pronouns: my, mine, your, yours, his, her, hers, its, our, ours, their, theirs, whose. These pronouns never require apostrophes.
Rule 7: To form the possessive of a singular abbreviation, add an apostrophe plus s.
Examples: the AMA's letter, the MD's diagnosis, USA's stand
Rule 8: To form the possessive of a plural abbreviation, add an s'.
Examples: the PhDs' dissertations, the RNs' orders, the CPAs' convention
A note about apostrophes that become place savers in contractions: Whenever a word or phrase becomes shortened by contraction, place an apostrophe at the point where the letters are omitted.
Examples: don't (do not), can't (cannot), rock 'n' roll (rock and roll), ma'am (madam). Confusion occurs when it is turns into it’s. Its color shows the possessive and means belong to it.
Joe parks his car in John and Jane's driveway with its blue color. He parks next to the Petersons' house and across the street from Edward's and Alfred's apartments. So, don’t worry, it’s apparent you know how to use the single polliwog of punctuation.
Now you have gained a polliwog's push to grow into a frog.