单项选择题
The （） stage air compressors are widely used on board the ship.
A.single B.Ⅱ C.Ⅲ D.multiple
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.
单项选择题 The （） is used to handle the ropes and wires.
