随机评估可以帮助我们了解发展中哪些措施有效，哪些无效。
Randomized evaluations can help us understand what works and what doesn't in development.
The magi brought valuable gifts, but that was not among them. This dark assertion will be illuminated later on.
科学是关于后果的知识，以及一个事实对另一个事实的依赖。