我想：丹中尉发现，有些事你是无法改变的，他不想被称为残废，就象我不想被称为傻瓜。

对我们星球的最大威胁是相信别人会拯救它。

科学是人类理解和改造世界的最有力工具。

在阈限阶段，共同体作为一种自发的、直接的和平等的人际关系出现。

Economics is the study of how societies use scarce resources to produce valuable goods and services and distribute them among different individuals. If we think about the definitions, we find two key ideas that run through all of economics:

"Every role I take on is a challenge, and that's what keeps me going."