conserve

我们必须谨慎节约使用有限的能源资源。

We must ___conserve our limited energy resources carefully.

农民们必须节约用水，尤其是在干旱季节。

Farmers must ___conserve their water supply, especially during dry seasons.

我们通过回收纸张来保护森林资源。

We ___conserve forest resources by recycling paper.