停电后在教室里上她

If you don't stay on the seventh floor to clean the practice room, what are you doing down here? Just as Ning Cheng was about to go down from the third floor, Mr. Mu's voice suddenly appeared in Ning Cheng's ears. Ning Cheng was startled. He had clearly seen that the door of Mr. Mu's stone house was closed just now. Why did it open in the blink of an eye?...