There was a time when we understood how things worked and how they were made, so we could build and repair them, or at the very least make informed decisions about what to buy.
曾经，我们都懂得一些机械的工作原理， 也知道它们是怎么制造出来的，所以我们能够自己制作和维修它们. 或者至少 基于我们的了解作出明智的购买决定。