You use them to refer to a group of people, animals, or things.
双语例句
例：
The Beatles – I never get tired of listening to them.
甲壳虫乐队–我百听不厌。
例：
Kids these days have no one to tell them what's right and wrong.
没人告诉现在的孩子们什么是对什么是错。
2.?（用于代替宾格“他”或“她”，不指明是男是女，有些人认为这种用法不正确）
You use them instead of 'him or her' to refer to a person without saying whether that person is a man or a woman. Some people think this use is incorrect.
双语例句
例：
It takes great courage to face your child and tell them the truth.