我们通过关掉不必要的灯来节约用电。

We try to ___conserve on electricity by turning off unnecessary lights.

她总是注意节约用水，避免浪费。

She always tries to ___conserve water and avoid waste.

她决定节省用水，只在必要时才浇花。

She decided to ___conserve water and only watered the plants when necessary.