Jinxianwen just sells brushes, looks at pens and buys fewer pens. Do you use your mouth to read a pen without buying it?

One day in Chinese class, I drew a pig on a piece of paper with a watercolor pen, and then gently stuck the paper on the back of a girl in front of me. Unexpectedly, she found it in a few minutes. She tore off the paper, looked at me with murderous eyes and said, "Hum, I'll get even with you after class."

I was puzzled and asked her, "Why do you feel there is a pig behind you?"