当随机化不可行时，匹配方法可以是一个强大的工具。
"Matching methods can be a powerful tool when randomization is not possible."
The best thing about art is that it can communicate without words.
预测未来的最好方法就是创造未来。
译文：聪明人注重细节，有智慧的人能发现苗头。