如图所示的电路中，电源电压恒为6V，R₁、R₂为定值电阻，R₁=10Ω．甲、乙均为电压表时，闭合S₁、S₂，两电压表示数之比为U_甲：U_乙=1：3．甲、乙均为电流表时，仅闭合S₁，甲、乙电流表示数I_甲、I_乙分别为（　　）

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

    The____(discover) of the principles of the absorption type of refrigeration in 1824 showed that liquefied ammonia (液氨) 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 ____(person) comfort. The first electrical air conditioning____(invent) by Willis Haviland Carrier in 1902. He was also known____the Father of Modern Air Conditioning.____ (he) invention was designed to improve the manufacturing process of a printing factory. By____(control) the temperature, the process was made more efficient.

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