水文学

例句：

1. 1.The study of water is essential for understandingthe Earth's climate system.
   研究水对于理解地球气候系统至关重要。
2. 2. Water resourcesare limited in many regions, and theirconservation is a pressing issue.
   许多地区的水资源有限，其保护是一个紧迫的问题。
3. 3. Theriver flows through the city, providingclean water for residents.
   这条河流流经城市，为居民提供清洁的水源。