key dam

例句：

1. 1.The key to solving this problem lies in understanding the underlying causes.
   解决这个问题的关键在于理解其根本原因。
2. 2. The construction of this key dam has been a long-awaited project for decades.
   这座关键水坝的建设是几十年来人们期待已久的项目。
3. 3.The safety of the key dam is crucial for the entire region's water supply.
   关键水坝的安全对于整个地区的供水至关重要。