In the 2nd version we learn that we have _____ our use of ____ ____ such as oil, gas and coal by nearly 80% over the last 50 years. We have replaced them now with a number of ______ forms of energy, such as ____, wind, and hydroelectric _____. Today, the world’s three billion _____ run on new fuel that ______ no CO2. And the safe, cheap _____ technology that started to be developed 80 years ago has _____, too.