短語(yǔ)詞組短語(yǔ)gravel sand layer 砂卵石層sandy gravel overburden layer 砂卵石覆蓋層sandy gravel replacement layer 沙礫石置換層gravel filled layer 填礫層gravel pervious layer 砂礫石透水層grit and gravel overburden layer 沙礫石覆蓋層sand gravel layer 砂卵石地層thick gravel layer 巨厚卵石層bottom gravel layer 底礫層 返回 gravel layer