And within that 10 to 20 years, you have to reinvest it just to maintain your existing say petrol station, gas station, that's the maintenance cost.

在这 10 到 20 年里，你必须再投资来维持你现有的加油站，这就是维护成本。

The experience of all ages and nations, I believe, demonstrates that the work done by slaves, though it appears to cost only their maintenance, is in the end the dearest of any.

我相信，所有时代和国家的经验都表明，奴隶所做的工作，虽然看起来只需要他们维持生计，但最终却是所有工作中最昂贵的。