UNIT 7I. CHOOSE THE CORRECT WORD

2050.b) Energy is very ..(1).. in modern life. People use energy ..(2).. run machines, heat and cool our houses, cook, give light, transport people and products ..(3).. place to place. Most energy nowadays comes from fossil fuels-petroleum, coal, and natural gas...(4).., burning fossil fuels causes ..(5).. . Also, ..(6).. we don’t find new kinds of energy, we will use up all the fossil fuels in the twenty-first century. Scientists ..(7).. to find other kinds ofenergy in the future. What might these sources of energy ..(8)..