单选题The packing installed in the pump stuffing box is lubricated by （）.Agravity and feed oil cupsBgrease cupsChand during installationDleakage through the stuffing box
单选题
The packing installed in the pump stuffing box is lubricated by （）.
A
gravity and feed oil cups
B
grease cups
C
hand during installation
D
leakage through the stuffing box
参考解析
解析：
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