sentences: a fossil fuel is a kind of natural resource & coal is a kind of fossil fuel ->  coal is a kind of natural resource  coal is a kind of natural resource & coal is a nonrenewable resource ->  coal is a kind of nonrenewable natural resource  coal is used to produce electricity by burning in coal-fire power stations & electricity is a kind of electrical energy ->  coal is used to produce electrical energy by burning in coal-fire power stations  coal is used to produce electrical energy by burning in coal-fire power stations & to produce something means to make something ->  coal is used to make electrical energy by burning in coal-fire power stations  coal is a kind of nonrenewable natural resource & coal is used to make electrical energy by burning in coal-fire power stations -> coal is a kind of nonrenewable natural resource that is used to make electrical energy