劳动分工受市场规模的限制。
The division of labor is limited by the extent of the market.
The method of psychology must be rigorously empirical.
世界上充满了那些小到足以让你心碎的东西。
The difference between a dream and a goal is action.
物理理论的美不仅在于其数学的优雅,还在于其解释和预测现象的能力。