剑鞘保护剑的锋利，自己却满足於它自己的迟钝。

Sustainability isn't just about planting trees; it's about planting the right trees in the right places for the right reasons.

资本主义社会的自由始终与古希腊共和国大致相同：奴隶主的自由。

释义：要了解过去和现在，以便灵活应变，适应变化。

"I don't think you can ever really understand a character until you've walked in their shoes."

护理是关于关心人，而不仅仅是治疗疾病。