The girl went to have piano lessons at the training center with her sister      she would stay for an hour.

A．who

B．where

C．which

D．what

某机器设备原始价值14万元，预计净残值率5%，预计使用年限6年，用年数总和法计提折旧，第2年应提的折旧额为（）万元。

A．2.532

B．3.165

C．3.33

D．2.664