使非正式

Because of the low efficiency of economy collectivization, collective property rights can"t last for a long time and central government has to communicate with community and peasants. Rural community collective property rights become subjective through balancing benefits by formal or informal trading. With the changes of political and economical environment, the contradiction of rural community property rights between fair and efficiency become more and more serious. Collective lands and collective enterprises advance to privatization gradually. There are two kinds of country collective property rights in the history of its evolution, one offer community common good and the other satisfy peasants" private demand. The collective property rights institution improvement brings efficiency because it privatizes the latter. Because of the limit of industrialization and civilization, land is still the last social welfare of peasants, so rural community must attain the collective property rights to control the pressure of population. Also community has to get money from collective economy.

本文分析的思路是；由于制度变迁的&路径依赖&，农村社区之间的利益分配边界在解放以后得以保持并在集体化过程中得到加强，为社区获得排他性集体产权奠定了基础；由于国家对农村经济的集体化效率极低而不可能长期维持，国家不得不与社区和农民对话，通过正式或非正式的交易平衡多方利益，社区集体产权获得实质性内容；随着政治、经济等环境的不断变化，社区集体产权公平与效率之间的矛盾同益明显，集体土地和集体企业逐渐朝私有化的方向发展；从农村社区集体产权制度变迁的历史来看，集体产权实际上包含两种形式：提供社区公共物品和满足社区农民个人需求，每一次集体产权的制度创新，都是使后者&私有化&而提高了集体经济的效率；但是，受我国工业化和城市化进程缓慢的制约，土地依然是农民最后的生存保障，农村社区必须保持对土地的集体产权以调节人口变化对土地的压力，社区组织行使职能也必须有一定的集体经济提供资金支持。

To make ends meet, Cubans are forced to rely on a vast informal economy.

为了要使端适宜，古巴人不得不仰赖巨大的非正式的经济。

On the other hand, the more important thing is because the urban housing is a kind of heterogeneity products.

另一方面，更重要的是由于城市住房是一种异质性产品。

Climate histogram is the fall that collects place measure calm value, cent serves as cross axle for a few equal interval, the area that the frequency that the value appears according to place is accumulated and becomes will be determined inside each interval, discharge the graph that rise with post, also be called histogram.

气候直方图是将所收集的降水量测定值，分为几个相等的区间作为横轴，并将各区间内所测定值依所出现的次数累积而成的面积，用柱子排起来的图形，也叫做柱状图。