The circulating recovery ground flow can reuse circulationmedium, especially for nitrogen and natural gas, the corresponding cost, risk and the extent of environment poll...
Ecosystems thus involve the circulation, transformation, and accumulation of energy and matter through the medium of living things and their activities.
因此，生态系统以生物及其活动作为媒介，涉及能量和物质的循环、转化和积累。
3
The newspaper is an ideal medium for most retailer s. its circulation area generally conforms to the retail trading area.