质量审核可由（）进行
A.内部高级职员
B.特殊训练的外来人员
C.内部的任何职员
D.血站管理人员
参考答案：A, B
The accident happened at nine o'clock in the morning ____ we were all busy with our work. [ ]
A. that
B. which
C. when
D. as
