阁楼式货架的特点是适合与重型搬运设备配合使用，上层货品搬运需配垂直输送设备。
参考答案：错
一组数据：3，2，1，2，2的中位数是_____，方差是_____．
— I called you at nine this morning, but there was no answer.
— Oh, sorry, I ______ with my sister in the shopping center.
A．shop
B．was shopping
C．shopped
D．will shop
