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單項選擇題

The shaft and spare parts（） should be well greased in order to avoid corrosion.

A.in the store room
B.in the cylinder
C.in the scavenge air box
D.in the water box

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單項選擇題

Water level controllers of the boiler must be kept operable to protect external steam-using plant from water “（）” danger.

A.carry off
B.carry down
C.carry on
D.carry over

單項選擇題

The （） of the gravity disc is too big It causes oil to flow through the water outletWe changed the disc and no oil is found in the water outlet.

A.gravity
B.diameter
C.circumference
D.cylinder