external economy短语¹⁸⁰⁰⁹⁸⁺¹ 基本例句 外在节约因素 For the sake of ecological benefit of forestry resources, the external economy of forestry production must be adjusted by adopting state- oriented contract or agent-oriented contract system. 必须对森林资源的生态效益实施国家定向合同购买或代理社会合同购买的办法来校正林业生产的外部性。 cnki