low NO低NOx燃烧lowadj.低的；少的；低落的；低声的；卑劣的；低等的adv.低地；低声地；低下地；廉价地n.低水平；低价；低谷v.哞哞叫low-cost houses经济适用住宅low-bed trailer(英:low-loader)低货架挂车low octane petrol低辛烷汽油low earth-orbit低地球轨道low growing plant矮生植物Low C/N ration低碳氮比lowpass equalizer低通均衡器low-lying hills低矮的丘陵low-rate filter低速过滤池low overpotential低过电压