irrigation sewage disposal

例句：

1. 1. The farmer used to irrigate his fields with rainwater.
   这位农民过去用雨水来灌溉他的田地。
2. 2. Thecity has a large network of irrigation canals.
   这个城市拥有一条庞大的灌溉运河网络。
3. 3. Irrigation is essentialfor maintaining the health of crops.
   灌溉对于保持农作物的健康至关重要。