短语词组短语Rack to Back Credit 背对背信用证full rack back position 齿条后退极限位置back rack 背后接线架;经纱张力调整机;后架back rack angle 纵向角Push Back Rack 后推式货架;后推式料架;后推货架Push -Back Rack 后推式货架back shading rack 反遮架;反向电阻 返回 rack back