Please make a joke.

One day, the teacher asked Xiaoming, "Where does the river flow?" Xiaoming sang, "The river flows eastward." The teacher asked again, "How many stars are there in the sky?" Xiao Ming sang, "The stars in the sky join Beidou." The teacher was very angry and said, "If you talk nonsense again, you will be punished." Xiao Ming sang "Let's go."