The history of public communication system

German scientists dug 50 meters down and discovered small pieces of copper¹. After studying these pieces for a long time, Germany announced that the ancient Germans 25,000 years ago had a nation-wide telephone net.
Naturally, the Russian government was not that easily impressed. They ordered their own scientists to dig even deeper. 100 meters down they found small pieces of glass and they soon announced that the ancient Russians 35,000 years ago already had a nation-wide fiber² net.
American scientists were outraged³ by this. They dug 200 meters down & found absolutely nothing. They happily concluded that the ancient Americans 55,000 years ago had cellular⁴ telephones.
note: fiber net——光纤网络　cellular telephones——蜂窝式移动电话

1 copper   

n.铜；铜币；铜器；adj.铜(制)的；(紫)铜色的

参考例句：

• The students are asked to prove the purity of copper.要求学生们检验铜的纯度。
• Copper is a good medium for the conduction of heat and electricity.铜是热和电的良导体。

2 fiber   

n.纤维，纤维质

参考例句：

• The basic structural unit of yarn is the fiber.纤维是纱的基本结构单元。
• The material must be free of fiber clumps.这种材料必须无纤维块。

3 outraged   

a.震惊的，义愤填膺的

参考例句：

• Members of Parliament were outraged by the news of the assassination. 议会议员们被这暗杀的消息激怒了。
• He was outraged by their behavior. 他们的行为使他感到愤慨。

4 cellular   

adj.移动的；细胞的，由细胞组成的

参考例句：

• She has a cellular telephone in her car.她的汽车里有一部无线通讯电话机。
• Many people use cellular materials as sensitive elements in hygrometers.很多人用蜂窝状的材料作为测量温度的传感元件。