经济发展理论研究的是经济系统如何产生不断改变它的力量。
Truth is the offspring of silence and unbroken meditation.
The way positive reinforcement is carried out is more important than the amount.
I never saw a wild thing sorry for itself. A small bird will drop frozen dead from a bough without ever having felt sorry for itself.
It is a curious fact that strikingly similar formations are found on opposite sides of the Atlantic.
一个有趣的事实是，大西洋两岸发现了惊人相似的地层构造。
全球贸易的未来取决于主要经济体能否在WTO框架内调和分歧。