- denoting possession in singular nouns, also in plural nouns not having a final -s［构成单数名词的所有格或构成不以s结尾的复数名词的所有格］：
the car's engine
汽车的引擎
Mrs Ross's son
罗斯太太的儿子
the children's teacher.
孩子们的老师。
词源
Old English, masculine and neuter genitive singular ending.