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單項(xiàng)選擇題

The successful operation of any engine or machine and （） depend on effective lubrication.

A.their no trouble period
B.their freely trouble period
C.its free trouble life
D.its trouble-free life

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單項(xiàng)選擇題

The starting of a marine diesel engine is generally carried out with the assistance of （）.

A.compressed air
B.electricity
C.hydraulic oil
D.compressing air

單項(xiàng)選擇題

The starting air system usually has （） to prevent starting if anything is not in order.

A.stop valves
B.interlocks
C.non-return valves
D.air vents