— When will the new bridge be completed?

— It is said that it _______ by the end of this year.

A．will complete

B．will have been completed

C．is completed

D．will be completing

长度为n的顺序存储线性表中，当在任何位置上插入一个元素概率都相等时，插入一个元素所需移动元素的平均个数为 。