单项选择题 If an air compressor is used to supply compressed air to outlets throughout the engine room and on deck of a vessel, the system is known as the （）.

单项选择题 The sensible heat of air is dependent upon the （）.

单项选择题 Which of the devices listed, when used on an electro-hydraulic steering gear, keeps the movement of the redder closely in step with the steering wheel?（）