We should conserve fuel, because it gets depleting nowadays. So, it is our duty to conserve it. If we fails to conserve the fuel, we will suffer, with lack of fuel.
So, we must organize the use of fuel.
If we doesn't save fuel, it will result in the massive depletion of the fuel, and the future generations will suffer.
They take more and more time to form. So, we must limit the usage of fuels, and conserve them.