在正式启动计量泵之前，应（）以确认电机的转向是否正确。
参考答案：点试一下泵
I'm calling to enquire about the position_______ in yesterday's China Daily. [ ]
A. advertised
B. to be advertised
C. advertising
D. having advertised
机组正常运行中氢纯度下降的原因和处理？
