穷人并非不理性；他们和任何人一样理性，但他们在非常不同的约束下行动。
The poor are not irrational; they are just as rational as anyone else, but they operate under very different constraints.
"The power of a story is in its ability to inspire action."
模形式的算术是数论更深层次对称性的反映。
How wonderful that we have met with a paradox. Now we have some hope of making progress.