2011 四川 第 47 题 单选题 区分题 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 参考答案D ☆ 收藏不会，直接看解析查看原卷 →