In the Xia family
"Mom, mom, why should I call you Xia Qian?"
"Because your father's surname is Xia and your brother's name is Xia Shen."
"..."
In the Shang family
"Mom, mom, why should I call you Shang Yu?"
"Because your father's surname is Shang, and your brother's name is Shang Yang."
"..."