凡陽必刚，刚必明，明则易知；凡陰必柔，柔必暗，暗则难测。
凡是陽性必刚强，刚强一定光明，光明则容易了解。凡是陰性必柔弱，柔弱一定陰暗，陰暗则难以预测。
反向传播最重要的地方在于它只是链式法则。
Trees are the earth's endless effort to speak to the listening heaven.
过去从未死去。它甚至还没有过去。
The poor are not irrational; they are just as rational as anyone else, but they operate under very different constraints.
