"Qian Xiaohei, do you know why I call Shen Xiaobai?"
"I know, when I was young, my grandma couldn't read. In order to distinguish us, one was black-haired and the other was white-haired. Then you were called Shen Xiaobai and I was called Qian Xiaohei."
"No, do you really think it's your grandma who can't read? She gave us couple names."
"Couple name?"