— He Shanghai. He will be back in three days.
A:has been to
B:has gone to
C:went to
D:was in
将某样本数据分析整理后分成6组,且组距为5,画频数分布折线图时,从左到右第三组的组中值为20.5,则分布两端虚设组组中值为____ 和____ .