词汇	eight bend
释义	eight bend 弯管或接头
随便看	summation formula of poisson summation formular summation frequency Summation Function summation gallop summation graph summation index summation instruction summation instrument summation law summation lever summation limit summation loop summation loudness decrement summation loudness increment summation matrix summation measuring apparatus summation measuring instrument summation meter summation metering summation method summation method of integration summation model summation network summation notation