Proficiency in a particular line

¡¡¡¡Gong sun Long , is a famous scholar lived in the State of Zhao during the Warring States Period (475-221BC). He had kept a circle skilled people around him. He often said, "A wise man should welcome anyone with a specialty."

¡¡¡¡One day, a man dressed in tattered and dirty clothes came to see him and said to him:" I have a special skill. "

¡¡¡¡Gong asked: "What is it?"