chief source of water for animals

例句：

1. 1. The chief of the police department is responsible for overseeing all operations.
   警察局长负责监督所有操作。
2. 2. He was the chief engineer on the project.
   他是该项目的主要工程师。
3. 3. The chief scientist in the lab has been working tirelessly to solve the problem.
   实验室里的主要科学家一直在努力解决这个难题。