多项选择题画二次锥面曲面图: {a,b,c}={1,1,1}
单项选择题两位分析者同时测定某一试样中硫的质量分数,称取试样均为3.5g,分别报告结果如下:甲:0.042%,0.041%;乙:0.0410%,0.0420%;丙:0.04099%,0.04201%。则( )