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單項(xiàng)選擇題

You must take good care of the drainage cock of the air control systemBecause （） leads scale formed which might malfunction the pilot control valve and other instruments.

A.the temperature
B.the rust
C.the pressure
D.the humidity

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單項(xiàng)選擇題

You increased the （） to 150 tons that’s why the fuel oil （）.

A.pumped speed；came out
B.pumping rate；overflowed
C.flowing rate；leaked out
D.flowed speed；spilled out

單項(xiàng)選擇題

Worn out ring grooves should be （） to standard dimension after being welded.

A.machined
B.bored
C.honed
D.drilled

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