单选题An advantage of a helical gear pump over a simple gear pump is that the helical gear pump is capable of （）.Amaintaining a steadier speedBdelivering liquids over greater distancesCoperating for longer periods of timeDproducing a smoother discharge flow
单选题
An advantage of a helical gear pump over a simple gear pump is that the helical gear pump is capable of （）.
A
maintaining a steadier speed
B
delivering liquids over greater distances
C
operating for longer periods of time
D
producing a smoother discharge flow
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