Atlanta was again the center of activities for a wide region, as it had been before its destruction, and the town was receiving a great influx of new citizens, both welcome and unwelcome.

亚特兰大又成了一个广阔地区的活动中心，就像它遭到破坏之前那样，同时它正在接纳一大批蜂拥而入的新市民，其中有受人欢迎的，也有不受人欢迎的。

At the same time, waste products such as carbon dioxide and water pass out of the cells and into the thin-walled capillaries. The capillary boundaries are the most important center of activity of the entire circulatory system.

静脉壁薄于动脉壁。它们引导来源于组织的含代谢废物的血液至心脏。静脉比动脉含更少弹性组织和结缔组织。