a type of roof that has plants growing on it that help to keep the building cool in summer and warm in winter 绿屋顶， 绿化屋顶 （种植植物以保持房屋冬暖夏凉）The firm designs and installs green roof systems. 该公司设计并安装了屋顶绿化系统。 Green roofs reduce the amount of storm water running off into drains. 绿色的屋顶减少了流入排水沟的雨水量。