标题：试举出三个我国古代的世界第一
一、文章正文
1. 第一项：世界最早的纸
我国是世界上最早发明纸的国家。据考古学家研究，西汉时期，我国已经有了纸的制造。东汉时期，蔡伦改进了造纸术，使得纸的制造技术更加成熟。据《中国造纸协会》官方网站介绍，蔡伦的造纸术被认为是世界上最早的纸制造技术。
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