river cross section

例句：

1. 1.The river has a wide cross section,which is suitable for fishing.
   这条河有一个宽阔的横截面，适合钓鱼。
2. 2. The engineermeasured the river cross section to determine thewater flow rate.
   工程师测量了河流横截面来确定水流速率。
3. 3. The map shows the rivercross section at different altitudes.
   地图显示了不同海拔高度的河流横截面。