The principles of conditioning apply equally to all species.

你停止尝试的那一刻，就是你开始失败的那一刻。

The poet’s words are the echoes of the eternal.

地质时间不仅漫长，而且复杂，过程以截然不同的速率运行。

A tannery's waste stream tells the story of its ethics more clearly than any mission statement.