首页 > 专业英语|国际贸易
[有奖翻译 ] 有奖翻译（难度增加）
In order to trace the history of underground cablesystems, it is necessary to examine the early days of the telegraph [1,2]. Thetelegraph was the first device utilizing electrical energy to become of anycommercial importance and its development necessarily required the use ofunderground construction. Accordingly, experimentation with underground cableswas carried on contemporaneously with the development of the apparatus forsending and receiving signals. Underground construction was planned for most ofthe earliest commercial lines. A number of these early installations are ofconsiderable interest as marking steps in the development of the extensiveunderground power systems in operation around the world.
［appleseden 在 2016-10-30 23:29:24 编辑过］