单选题Before liquid can flow into a pump, the air in the suction line must be （） sufficiently to cause the liquid to flow into the suction chamber.AfilledBevacuatedCcompressedDcharged
单选题
Before liquid can flow into a pump, the air in the suction line must be （） sufficiently to cause the liquid to flow into the suction chamber.
A
filled
B
evacuated
C
compressed
D
charged
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