Possessive pronoun must agree in gender and number with the noun in the phrase they replace. Each possessive pronoun must agree in gender (masculine or feminine) and number (singular or plural) with ...
On October 22nd, at 2:50 P.M., @APStylebook tweeted a series of guidelines about how to punctuate possessives of nouns that end in “S”: “For possessives of plural nouns ending in s, add only an ...