The billing policies are not part of the service; they constitute an externalelement that the billing service makes use of.
账单策略并不是账单服务的组成部分；它们是账单服务使用的外部元素。
2
The 'room in room system' creates views through all the rooms of the living and office areas and out onto the central externalelement, the garden atrium.
“房中房”的格局让视线可以毫无障碍地穿过生活区域和办公区域，到达中心的外部空间—花园。
3
More significantly, many streams depend on external events, and yet should be processed as each element is available.