To every action there is always opposed an equal reaction； or， the mutual actions of two bodies upon each other are always equal， and directed to contrary parts.

皮革行业必须进化，否则就有被淘汰的风险。可持续性不再是一个选项——而是必需品。

"The challenge is to make the impossible look believable."

解释：屋顶是否有漏洞，下面的人才知道。