The clerks were at work so ____ that nobody realized it was already lunch time.

A．accurately

B．absently

C．aggressively

D．attentively

当一段进料缓冲罐液位低时，应检查和处理聚结分离器罐底、一反进料缓冲罐罐底去裂解汽油进料罐阀门的开度或泄漏。