表达 “the black sheep of the family” 指 “家中声名狼藉的成员”，也就是汉语里说的 “败家子，害群之马”。如果某人被称作 “the black sheep of the family”，这个人则可能做过错误的决定或与其家庭成员格格不入。这个表达也可以缩写为 “the black sheep”。
My brother is the black sheep of the family – he fell out with the rest of the family years ago and no one has spoken to him since.
Aunt Susan became the black sheep of the family after she went to prison for tax evasion.
A. Who is the black sheep of your family?
B. My little brother John. He is always in trouble and is so different from the rest of the family.