单项选择题
The rate of heat transfer in a water-tube auxiliary boiler can be increased by （）.
A.operating the boiler at less than normal water level B.installing fins on the firesides of water-tubes C.increasing the amount of excess air to the burners D.treating the boiler water with chemical oxygen scavengers
单项选择题 The term “proper metering”, as applied to a diesel fuel injection system, can be best defined as （）.
单项选择题 Connecting rods in a diesel engine are used to connect the （）.
单项选择题 Fuel oil transfer systems used onboard diesel propelled vessels are required to have （）.
