单项选择题
The air compressor pumps air to the （）.
A.air cylinder B.combustion chamber C.steam drum D.expansion tank
单项选择题 The （） stage air compressors are widely used on board the ship.
单项选择题 The air filter is fixed in the （） of an air compressor.
单项选择题 The （） belongs to the mooring equipment.
