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。

The past is a ghost, the future a dream, and all we ever have is now.

Psychology must be a science of functions, not just a science of facts.

Music is the voice of the soul. If you can speak, you can sing. If you can walk, you can dance.

解决全球饥饿的关键不仅是提高产量，还要改善营养质量。