价的概念是理解分子结构的关键。

Collaboration across industries and borders is essential to meet the world's energy needs.

The power of abstraction is that it allows us to reason about systems at a higher level, without getting bogged down in the details.

从富裕社会中解放出来并不意味着回归健康和强健的贫困、道德纯洁和简单。