Not until 1866 was the fully successful transatlantic cable finally laid.
直到1866年第一条横跨大西洋的电缆才完全成功的架通。

The boy finally cleaned the clocks of him.
那男孩终于打败了他。

When the persuading and the planning for the western railroads had finally been completed,the really challenging task remained:the dangerous,sweaty,backbreaking,brawling business of actually building the lines.
当有关西部铁路的说服和规划工作终于完成后，真正艰难的任务还没有开始；即危险，吃力，需要伤筋动骨和吵吵嚷嚷的建造这些铁路的实际工作。