gravel ballast砾石: gravel; grail; dirt道碴: ballast aggregate; ballast卵石道碴: pebble ballast砂石道碴层: sand ballast mat碎石道碴: broken stone metaling; crushed stone ballast下载手机词典可随时随地查词查翻译关注微信公众号:chachacidian,回复:砾石道碴,即可在微信中查询翻译