提出“自然教育”思想的代表人物是（） ["狄德罗","爱尔维修","卢梭","夸美纽斯"]
欲测某水泥熟料中的SO3含量，由五人分别进行测定.试样称取量皆为2.2g，五人获得五份报告如下.哪一份报告是合理的？（） ["2.0852%","2.085%","2.08%","2.09%","2.1%"]
滴定分析法要求相对误差为±0.1%，若称取试样的绝对误差为0.0002g则一般至少称取试样：（） ["0.1g","0.2g","0.3g","0.4g","0.5g"]
航向台发射：（） ["水平极化波","垂直极化波","水平极化波和垂直极化波","圆极化波"]
今欲配制一升0.01000mol/LK2Cr2O7（摩尔质量294.2g/mol）溶液.所用分析天平的准确度为±0.1mg.若相对误差要求为±0.2%，则称取K2Cr2O7应称准至：（） ["0.1g","0.01g","0.001g","0.0001g","0.02g"]
菌肥
