单选题Centrifugal pumps, however, can be designed with a number of impellers （） to attain a large amount of liquid.Ain seriesBin parallelCassembledDtogether
单选题
Centrifugal pumps, however, can be designed with a number of impellers （） to attain a large amount of liquid.
A
in series
B
in parallel
C
assembled
D
together
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