时间不是一条线；它是一个维度，就像空间的维度一样。
The natural effort of every individual to better his own condition， when suffered to exert itself with freedom and security， is so powerful a principle that it is alone， and without any assistance， not only capable of carrying on the society to wealth and prosperity but of surmounting a hundred impertinent obstructions with which the folly of human laws too often encumbers its operations.
Development economics is ultimately about improving people's lives.