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單項選擇題

Impurities from the boiler water surface can be removed through the （）.

A.safety valve
B.blow down valve
C.scum valve
D.feed check valve

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單項選擇題

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

單項選擇題

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

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