We should try to save water.

我们应设法节约用水。

Save water for the future of our earth.

为了地球的未来，节约每一滴水。

On behalf of the student union, I'd like to put forward a proposal to save water on our campus.

我谨代表学生会，提出校园节水的提议。

Our problem is how to save water.

我们的问题是如何节约水。

He wants to save water?

想节水吗？