Over the past 10 years, carriers have installed fiber-optic cable throughout every major metropolitan area in the U.S. and have standardized the use of SONET equipment.
Over the past 10 years, carriers have installed fiber-optic cable throughout every major metropolitan area in the U.S. and have standardized the use of SONET equipment.
在过去十年中，电话公司在美国的各个大城市中都铺设了光缆，并对SONET设备的使用进行了标准化。