参考答案: B
详细解析:
正如所有的国际电信联盟标准一样，降低能耗是发展中考虑的关键。相信下一代网络比起传统的网络确实能够降低可观的能耗。
As with all ITU standards，reduce energy consumption is a key factor taken into account at development stage.Indeed NGNs are believed to offer significant saving（ ）traditional networks.
A. of
B. over
C. at
D. in
参考答案: B
详细解析:
正如所有的国际电信联盟标准一样，降低能耗是发展中考虑的关键。相信下一代网络比起传统的网络确实能够降低可观的能耗。