Explain the rules for forming the possessive ca... - SS1 English Grammar: Nouns possessive Question

There are a few simple rules for forming the possessive case of nouns. First, nouns that end in s or z add an apostrophe only ('). For example, the possessive form of "the dog" is "the dog's." Second, nouns that end in ch, sh, ss, or x add an apostrophe and an s ('s). For example, the possessive form of "the church" is "the church's." Third, nouns that end in a vowel followed by y add an apostrophe and an s ('s). For example, the possessive form of "the boy" is "the boy's." Fourth, nouns that end in a consonant followed by y change the y to i and add an apostrophe and an s ('s). For example, the possessive form of "the city" is "the city's.