短語(yǔ)詞組短語(yǔ)gravel road base 碎石路基oiled gravel road 瀝青礫石路gravel road surface 砂礫路麪gravel producing for road 路用碎石生産Graded gravel road structural design 級(jí)配碎石路麪結(jié)搆設(shè)計(jì)scatter gravel on the road 把砂礫撒在路麪上 返回 gravel road