Most of them come from seniors, and some students are willing to borrow used computers from seniors. There are precious study materials and important notes in these computers, and there are many notes and experience records in the teaching materials, which will make freshmen have a knowledge to fill in the learning process, which is also a new harvest, while reducing their own investment costs, which is also very kill two birds with one stone. In addition, through the second-hand group, seniors and sisters will sell their learning materials at low prices, thus obtaining second-hand teaching materials. I hope my answer is helpful to you. Welcome to adopt my answer. Thank you.