“砂砾层”造句

沙砾覆于铁质土层与砂砾层之上.
Gravelly - sand over an iron - pan and gravel layer.

小石头、砂砾层也可用来做隔绝层,以保持水分,降低土壤的温度.
Pebbles and gravel also insulate the soil to keep surface temperatures low and preserve water.

古河谷的边缘地带,往往缺失底部的河床相砂砾层.
The edge of the incised - valley lacked the sand - gravel bed of the river channel at the bottom.

• #砂砾层