高炉冶炼中使用的纯石灰石含()为56%,CO2为44%。
A.SiO2
B.MgO
C.CaO
参考答案:C
Yesterday was the twins’ birthday, ________ presented a gift.
A . each of them B each of whom C both of them D both of whom
成本控制方法中的表格法的优点是()。
A.灵活
B.适用性强
C.信息量小
D.能准确表达绝对偏差
E.可借助计算机处理数据