flashv.闪光；闪现；掠过；忽然...；亵渎性暴露n.闪光（灯）；恍然大悟；一刹那；闪现；[计算机]Adobe公司的动画技术flash in将底片成正片再曝光以改变其

1. A layer of coarse gravel is often placed around the drain tile.
   常常在排水瓦管周围铺一层粗石砾。