step wave

例句：

1. 1.The ocean waves crashed against the shore.
   海浪冲击着海岸。
2. 2. The ripples spread out across the lake.
   涟漪扩散到湖面上。
3. 3.The step wave was caused by a sudden change in wind direction.
   步骤波是由风向突然改变引起的。