The AIDS epidemic offers an example. The broad goal, of course, is to end the disease. The highest-leverage approach is prevention. The ideal technology would be a vaccine that gives lifetime immunity with a single dose. So governments, drug companies, and foundations are funding vaccine research. But their work is likely to take more than a decade, so in the meantime, we have to work with what we have in hand-and the best prevention approach we have now is getting people to avoid risky behavior.
艾滋病就是一个例子。毫无疑问，总的目标是消灭这种疾病。最高效的方法是预防。最理想的技术是一种疫苗，只要注射一次，就可以终生免疫。所以，政府、制药公司、基金会在资助疫苗研究。但是，这种研究工作很可能花费十几年时间。因此，与此同时，我们必须使用现有技术——目前最有效的预防方法就是设法让人们避免那些危险的行为。
Pursuing that goal starts the four-step cycle again. This is the pattern. The crucial thing is to never stop thinking and working-and never do what we did with malaria and tuberculosis in the 20th century-which is to surrender to complexity and quit.
要实现这个目标，又可以采用四步循环。这是一种模式。关键是永远不要停止思考和行动——我们千万不能再犯上个世纪在疟疾和肺结核上犯过的错误——那时我们因为它们太复杂而放弃了采取行动。
The final step-after seeing the problem and finding an approach is to measure the impact of the work and share tha successes and failures so that others can learn from the efforts.
在发现问题和找到解决方法之后，就该进行最后一步——评估工作结果，将你的成功经验或者失败经验同其他人分享，这样他们就可以从你的努力中有所收获。
You have to have the statistics, of course. You have to be able to show, for example, that a program is vaccinating millions more children. You have to be able to show, for example, a decline in the number of children dying from these diseases. This is essential not just to improve the program, but also to help draw more investment from business and government.
当然，你必须有一些统计数字。你必须让他人知道，例如，你的项目为几百万儿童接种了疫苗。你也必须让他人知道，儿童死亡人数下降了多少。这些都是很关键的，不仅有利于改进项目，也有利于从商界和政府得到更多的帮助。
