Not bound. The Waiyantong reading pen shows that there is no text here because the Yunxiang pen can only perform a limited number of cloud readings when it is not bound. If the number of readings exceeds the number, it will prompt that there is no content in the cloud words. Through the Waiyantong App Binding the pen solves the problem. Foreign Language Teaching and Learning is a self-owned trademark brand registered by Beijing Foreign Studies University Foreign Language Teaching and Research Press. Currently, the pen used in primary and secondary school classrooms to accompany Foreign Language Teaching and Learning textbooks is the Foreign Language Reading Pen.