expanding ring

例句：

1. 1.The expanding ring is causing the planet torotate faster.
   扩张环正在使行星旋转得更快。
2. 2. The expanding ring is responsible for themovement of the moon.
   扩张环负责月亮的运动。
3. 3.The expanding ring has been causing problems forastronauts.
   扩张环给宇航员带来了问题。