聚集效应及其演变导致城市中心区形成和向多中心演化。在向多中心深化这一过程中，商留功能和商务功能在城市多中心之间的动态调整，导致了现代化城市中心商务区（CBD）的形成。重庆解放碑商圈及其演化的过程，充分验证了城市中心区演化与CBD形成的内在机理。CBD形成与城市中心区演化的这一内在机理表明；对CBD的规划和政策引导，一定要遵循城市中心区演化的经济规律，尤其要遵循商务活动聚集经济性的原则；对CBD功能的定位应主要体现为对商务活动的聚集，而不能只图眼前的利益“兼收并蓄”；CBD的选址既可以是原城市中心区，也可以在原城市中心外围另劈新地。

Agglomeration Effects and its evolution lead to the formation and further evolution to multi centers of a city's original center.During the further evolution to multi centers, there exists a rule which is proved to be true by the example of the formation and evolution of The dynamic adjustment of functions between business and trade within centersdrive the formation of a modern city's central business district(CBD).This rule discloses the following facts in planning and policy making of CBD:we must obey the natural rules of city centers' evolution,including the rules of Agglomeration Effects;we must lead CBD to mainly agglomerate business,not agglomerate everything;we can choose the original city center or other place out of the original city center as a CBD's location.

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