usfsCOCA⁸¹²⁰⁸ 基本例句 United States Frequency Standard If operators reckon there is money to be made running mobile networks even in some of the poorest parts of the world, have USFs had their day? 如果各大运营商认为在世界上一些最贫困的地区经营移动通讯网络能够赢利，那么 USF是否终于得以使用了？ ecocn