Machines replaced men. 机器代替了人力

321. The phenomenal revolutionary power of black gold.
     黑色黄金非凡的革命性能量
322. With its help,
     因此
323. A country of farmers became a country of agricultural industrialists.
     农业国家变成了机械化农业国家
324. Machines replaced men.
     机器代替了人力
325. A liter of oil generates as much energy...
     一升石油产生的能量
326. As 100 pairs of hands in 24 hours,
     相当于100双手劳作24小时
327. But worldwide only three percent of farmers have use of a tractor.
     但是世界上仅百分之三的农民使用拖拉机

来自《家园 第一部分 Home Part1》第 324 行