单词	背腹受敌
释义	同背腹受敵
随便看	roughness roughness, absolute roughness allawance roughness allowance roughness angle roughness average roughness average {=ra} roughness coefficient roughness comparison specimen roughness drag roughness element roughness elements roughness, equivalent roughnesses roughness factor roughness grade number roughness height roughness, hydraulic roughness layer roughness length roughness meter roughness number roughness of manner roughness of river beds roughness of skin