摘要
阅读理解Mr Guo is a teacher from Xi9an.He asked his students to hand in their homework through a QR code(二维码).“We spent an hour or two in class learning how to generate the codes,and in the end everything gets easier,”said Guo.“When students finish the homework,they keep it on WeChat.Then,each student makes his own QR code and gives it to me.So I can check their work anywhere using my computer or phone.”
