Wei shenme—why?
A German guy was married with a Chinese woman. He had a Chinese name, Te-mao Wei. One day, the German met a Chinese elderly man, the two exchanged greetings . The elderly man asked: "What is your surname?(nín guì xìng?)" The German guy answered: "My surname is Wei(wǒ xìng Wei)." The elderly man: "Wei shenme?" German guy: "Why? Gee, Do I need the reason if my surname is Wei?"
"Wei shenme" in Chinese means Why, but “Wei shenme” the elderly man asked here means “Surname Wei, what is your given name?