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單項(xiàng)選擇題

All bilge suction must be fitted with suitable （）, which in the machinery space would be mud boxes positioned at floor-plate level for easy access.

A.strainers
B.valves
C.elements
D.separators

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單項(xiàng)選擇題

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

單項(xiàng)選擇題

Sealing in pump shaft is achieved by means of the （）.

A.gasket
B.packing
C.washer
D.spring

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