题目

发展生产力需要改变生产关系中同生产力不相适应的环节和方面，这主要是因为（) A . 生产关系对生产力具有促进作用 B . 生产关系对生产力具有阻碍作用 C . 生产关系对生产力具有反作用 D . 生产力是最活跃、最革命的因素 答案：CI'm sorry you can't go in now. The room ________ yet. A. hasn't been cleaned B. hasn't cleaned C. isn't been cleaned D. isn't being cleaned