关于一个屋顶项目排水的地方的，falls这个地方实在研究不出来
有没有大神给我指点迷津 
Roof coverings to falls and cross falls and sloping not exceeding 15 degrees from the horizontal to gutters.
有没有大神给我指点迷津 Roof coverings to falls and cross falls and sloping not exceeding 15 degrees from the horizontal to gutters.
