1. civilization advances by extending the number of operations we can perform without thinking about them.
2.writting which is itself a form a code。
3.Sumerian the most profound innovation in sunerian writing ,how ever , was the cognitive leap that took place from a simple .
5.jacobs not only challenged conventional views on contemporary urban development in her writing ang speaking.she thought cities are source, not the recipient ,.jacobs focused on the primacy of urban konwledge in agricicultural productivity, as embodied in both practical.
6.agriculturre is not even tolerably productive unless it in corporates many goods and services produced in cities and transplanted from cities.(农业不仅仅是种草，相关知识产生的话费也是增进农业的重要部分)。
7.the creation of new work was and still is a powerful driver of economic development: every time new work -a new production recipe -is created ,it in turn creates new possibilities for the division of labor .according to jacobs the interaction betwween the creation of new recipes and the division of labor required.(新食谱和新的劳动分工相互作用)。