经济学的研究最终是对人类行为及其后果的研究。
The study of economics is ultimately the study of human behavior and its consequences.
我对自己的外表非常有信心。
Nature is a book, and each species is a chapter, each species is a story.
野外的规则是适者生存。你必须强壮、聪明、适应力强才能生存下来。