皮带转动的传动比计算公式为I=（） ["A、n1n2=D2D","1B、n1D1=n2n2","C、n1n2=n1D2","D、D1/n1=D2/n2"]
对某食品中粗蛋白进行了6次测定，结果分别为59.09%、59.17%、59.27%、59.13%、59.10%、59.14%，标准偏差为（）。 ["0.06542","0.0654","0.066","0.065"]
物资内在质量检验的具体内容？
螺距T是指（）轴向距离 ["A、相邻两牙在中径线对应点间","B、两牙顶点","C、相邻两牙量小径","D、牙根"]
用经校正的万分之一分析天平称取0.1克试样，其相对误差为（）。 ["±0.1%","+0.1%","-0.1%","无法确定"]
原料油为什么要过滤？
