highway level crossing out door audible device

例句：

1. 1. The highway is the main artery connecting the city to the countryside.
   这条高速公路是连接城市和乡村的主要动脉。
2. 2.The driver was forced to stop at a highway service station for fuel.
   司机被迫在一个高速公路服务站停下来加油。
3. 3. The construction of new highways has greatly improved transportation in this region.
   新高速公路的建设极大地改善了该地区的交通。