A
A.The material flows in human settlements物质在人类居住地的流动
B
B.The material flows in human socio-economic systems物质在人类社会经济系统中的流动
C
C.The material flows formed by human activity disturbance in the natural earth surface物质在人类活动干扰下形成的自然地表环境系统中的流动
D
D.The material flows formed by natural forces in a socio-economic complex system物质在自然力作用下形成的社会经济复合系统中的流动
