bottom on建立在bottomn.底部；底端adj.底部的v.触底；打(基础)bottom breezing system下送风bottom flushing outlet冲砂底孔bottom lateral bracing底斜支撑bottom ash and fly ash焚烧灰渣bottom slide of saddle刀架底板bottom-emptying skip底卸式箕斗bottom die of sand core砂芯下模体bottom diversion outlet导流底孔bottom line of morality道德底线bottom-line issues.盈亏结算报告