短語詞組短語gravel road base 碎石路基oiled gravel road 瀝青礫石路gravel road surface 砂礫路面gravel producing for road 路用碎石生產(chǎn)Graded gravel road structural design 級(jí)配碎石路面結(jié)構(gòu)設(shè)計(jì)scatter gravel on the road 把砂礫撒在路面上 返回 gravel road