loop command

例句：

1. 1. The car is in a loop around the park.
   汽车在公园里绕了一个圈。
2. 2. The train follows a loop route to the station.
   火车沿着一条环线到站。
3. 3. The game has a loop ending at the end of the level.
   游戏有一个环路，在关卡结束时结束。