题目内容：

    Mrs. Li is a teacher from Shenyang. She asked her students to hand in their homework through a QR code (二维码). "73. When students finish the homework, they keep it on WeChat. So I can check their homework everywhere using my computer or mobile phone." said Li.

"The paper is not easy to keep, but the code is easy to keep and share," Li said. 74. "It is worth trying to use new technology in education. Education itself is a kind of creation. 75. I don't want my students to fall behind the times."

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