短语词组短语balanced -draft control 负压调节;引风调节balanced healthy draft 均衡通风balanced draft boiler 平衡通风锅炉balanced draft furnace 具有引风及鼓风的平衡通风炉膛balanced draft sampling 平衡吸气取样balanced draft system 平衡通风系统draft balanced 均衡通气 返回 balanced draft