有很多种
最简明醒目的是:SAVE WATER 要比较柔和委婉的是:PLEASE SAVE WATER 还有一个是:SAVE THE WATER 或者 treasure water resources
保护环境就是protect the environment；或者protect our environment,或者The protection environment
一起说可以这样protect environments,treasure water resources；或者protect our environment, cherish water resources