可持续性不再是一个选择；它是皮革鞣制未来的必要条件。
Sustainability is no longer an option; it's a necessity for the future of leather tanning.
In mathematics, the art of proposing a question must be held of higher value than solving it.
生命太短，不能长时间记恨。
读书时刻苦用心，才能达到一字千金的层次。