基本解释[机] 统一标准粗牙螺纹词组短语短语unified national coarse thread 统一标准粗牙螺纹unc unified national coarse thread 统一标准粗牙螺纹unified coarse thread series 统一的标准粗牙螺纹系列Unified coarse thread hand taps 统一标准粗牙丝攻专业释义机械工程统一标准粗牙螺纹统一粗牙螺纹