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單項選擇題

In an ordinary four-stroke engine the exhaust valves open （）

A.after TDC
B.before TDC
C.after BDC
D.before BDC

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單項選擇題

In an ordinary diesel engine the fuel injection begins （）

A.after TDC
B.before TDC
C.after BDC
D.before BDC

單項選擇題

In an oil cooler circulated by sea water, the oil is at a larger pressure, the result being that any leak in the cooler will mean a loss of （）.

A.oil
B.sea water
C.refrigerant
D.fresh water