's與s' 既問題

Example:
This is Amy's apple.
These are students' handbook.
多個一個學生就叫students
佢後面有個s,,,咁就唔就加多個s...直接叫students'

's = 屬於某主體的
如 Mary's book = 瑪筣的書本
s' = 屬於眾數主體的
如 the boys' teacher = 那班男孩子的老師

's 同埋s'都係屬有名詞,
單數屬有名詞:nouns(名詞)+'s , 例:a boy's
複數屬有名詞:以s結尾的nouns(名詞)+' ,例: two boys'