major relay center

例句：

1. 1.The major relay center is located in the heart of the city.
   主要接力中心位于市中心。
2. 2.The major relay center plays a crucial role in maintaining communication between different parts of the country.
   主要接力中心在维护国家不同地区之间的通信方面起着至关重要的作用。
3. 3.The major relay center was upgraded to handle more traffic than before.
   主要接力中心升级后，处理的交通流量比以前多了。