up stream

例句：

1. 1. The river flowsthrough the town and its upstream areais rich in wildlife.
   这条河流穿过这个城镇，它的上游地区野生动物丰富。
2. 2. Thecompany's main source of revenue comesfrom upstream operations.
   这家公司的主要收入来源是上游业务。
3. 3. The scientists studied the behaviorof fish in their upstream habitat.
   科学家们研究了鱼类在其上游栖息地的行为。