The history of air conditioners(空调) started in the early days with the need to preserve food. The food___41___is kept at room temperature spoils easily due to the growth of bacteria. At temperature below 4℃, the growth of bacteria reduces___42___(rapid). As a result of the development in food refrigeration, other following applications include air conditioning and manufacturing processes.

The___43___(discover) of the principles of the absorption type of refrigeration in 1824 showed that liquefied ammonia(液氮) could cool air. At first, the commercially available use of air conditioning applications was based on the need to cool air for industrial processes rather than___44___(person) comfort. The first electrical air conditioning___45___(invent) by Willis Haviland Carrier in 1902. He was also known___46___the Father of Modern Air Conditioning.___47___(he) invention was designed to improve the manufacturing process of a printing factory. By___48___(control) the temperature, the process was made more efficient.

The Carrier Air Conditioning Company of America was set up by him___49___(meet) the demand of better productivity in the workplace. Today, Carrier Corporation is___50___biggest air conditioner manufacturer and marketing corporation in the world in central air conditioning.