2011 Sichuan Question 47 Single-choice Differentiating 2011_省自主命题(四川) 47. If you want to use energy free, you have to A. sign an agreement with the governmentB. pay around £14,000 for the equipmentC. sell the roof to some energy companiesD. keep the roof unchanged for within 25 years Answer keyD ☆ SaveCan't do it, show the explanation查看原卷 →