题目解析：
用两个人名来定位，定位到：Presociological thinkers like Frederick Law Olmsted, the founder of the movement to build parks and recreation areas in cities, and Jacob Riis, an advocate of slum reform, urged the nation's leaders to invest in improving the urban environment, building parks and beaches, and making better housing available to all. 由此可以看出，Olmsted和Riis都希望improving the urban environment（改进城市环境），也就是想要improve the conditions of life（改善城市生活条件）。所以选择C。A选项的empirical research是其他sociologists做的，不是他们两个的共同点；B选项无提及，D选项的reduce the rapid growth无提及。
In the early twentieth century, the science of sociology found supporters in the United States and Canada partly because the cities there were growing so rapidly. It often appeared that North American cities would be unable to absorb all the new comers arriving in such large numbers. Presociological thinkers like Frederick Law Olmsted, the founder of the movement to build parks and recreation areas in cities, and Jacob Riis, an advocate of slum reform, urged the nation's leaders to invest in improving the urban environment, building parks and beaches, and making better housing available to all. These reform efforts were greatly aided by sociologists who conducted empirical research on the social conditions in cities. In the early twentieth century, many sociologists lived in cities like Chicago that were characterized by rapid population growth and serious social problems. It seemed logical to use empirical research to construct theories about how cities grow and change in response to major social forces as well as more controlled urban planning.
