how long something lasts is a measure of how long that something is available & as the use of a resource decreases , the length of time that resource being available will increases ->  as the use of a resource decreases, the length of time that that resource will last increases  as the use of a resource decreases, the length of time that that resource will last increases & to last longer means the length of time that something lasts increases ->  decreasing the use of a resource causes that resource to last longer  oil is used for producing electricity0 & fossil fuels are a kind of energy resource ->  a fossil fuel supply is a kind of resource  decreasing the use of a resource causes that resource to last longer & a fossil fuel supply is a kind of resource ->  decreasing the use of a fossil fuel supply causes that fossil fuel supply to last longer  oil is used for producing electricity & oil is a kind of fossil fuel ->  fossil fuel is used for producing electricity  fossil fuel is used for producing electricity & as the use of something decreases, the use of things used to produce that something decreases ->  as the use of electricity decreases, the use of fossil fuels decreases  oil is used for producing electricity1 & as the use of something decreases , the use of the source of that something will decrease ->  as the use of something decreases, the use of the supply of that something decreases  as the use of electricity decreases, the use of fossil fuels decreases & as the use of something decreases, the use of the supply of that something decreases ->  as the use of electricity decreases, the use of a fossil fuel supply decreases  decreasing the use of a fossil fuel supply causes that fossil fuel supply to last longer & as the use of electricity decreases, the use of a fossil fuel supply decreases ->  decreasing the use of electricity causes a fossil fuel supply to last longer  decreasing the use of electricity causes a fossil fuel supply to last longer & to decrease something means to reduce something -> reducing the use of electricity causes the fossil fuel supply to last longer