three R's背环threenum.三n.三；三个adj.三个的three diamension traction三维牵引Three is the lucky number三是幸运数字three - dimension model三维建模three-protection design三防设计three phase multivibrator三相多谐振荡器three-ring transmission三环传动three-way reinforcement三向配筋three phase ac controller三相交流调压器Three cats. A family.三只猫。一个家庭。three-dimensional order三维有序