levee grade

例句：

1. 1. The engineers are assessing the levy grade of the flood control system.
   工程师们正在评估防洪系统的堤防等级。
2. 2.The construction of the levy grade is crucial for the stability of the riverbed.
   堤防等级的建设对于河床的稳定性至关重要。
3. 3. The levy grade must be designed to withstand heavy rainfall and flooding.
   堤防等级必须设计成能够承受大雨和洪水的冲击。