people person humankind human race human being humanity 怎么用

题目

people person humankind human race human being humanity 怎么用
people
person
humankind
human race
human being
humanity 这几个表示人的词怎么用啊,如果嫌麻烦的话告诉我哪些可以用复数就好,即可以加定冠词a的?
那个lost_property

答案

只有a person
a human being可以加a