数据6，8，8，x的众数有两个，则这组数据的中位数是（ ）。
7
我国的民族自治地方分为（）、（）和自治县（）三个行政级别。
下列哪些选项是国际学术会议的开场语句？（）
A.I am very pleased to have this opportunity to....
B.First let me express my gratitude
C.Now after a short introduction I would like to read to the main part of my paper...
D.The last part of my report will be devoted to....
