GRE Reading Comprehension: ETS Official Practice 150-GRE OP150: 阅读 - HPYG6DJ4SB3GDR0W1

Years ago, consumers in Frieland began paying an energy tax in the form of two Frieland pennies for each unit of energy consumed that came from nonrenewable sources. Following the introduction of this energy tax, there was a steady reduction in the total yearly consumption of energy from nonrenewable sources.