principal river

• 干流

principal river的用法和样例：

例句

1. The sand and gravel in the Yangtze river is good building and filling materials.
   摘要长江中下游干流河道内的砂石是较好的建筑和填筑材料。
2. Gezhouba Water Control Project on the Yangtze River is the first large-scale construction of water conservancy projects.
   葛洲坝水利枢纽工程是长江干流上兴建的第一座大型水利工程。