A：一国两制
B：民族平等、团结和共同繁荣
C：民族平等、团结、互助、和谐
D：民族区域自治制度
一个等腰但不等边的三角形，它的角平分线、高、中线的总条数为____ 条．
A____ great importance to this research, the professor spared no efforts to do the experiment.
Who is ____ (old) of you three?
