题目

His clock is nice, but hers ______. A . don't B . aren't C . isn't D . am not 答案：C11．比例图表示某陨石样品中各种元素含量，此陨石样品中不可能含有的化合物是（　　）A．Al2O3B．SiO2C．CaCO3D．KOH