translation.en: In a cruel reversal, after we had almost conquered smallpox -- and this is what you must learn as a social entrepreneur, the realm of the final inch.
translation.zh: 在我们马上要消灭天花的一个关键时刻 这也是你作为一个社会企业家应当学习的，就是到了最后的那一个拐点上该怎么做