The Process of Gaining

共享题干题                                                                         （一）
                                                   The Process of Gaining or Losing Weight
阅读材料，回答下列的问题。
         The process of gaining or losing weight can be explained by comparing your body to your car. Both run ____________（51） fuel, food for your body and gasoline for your car. Both ____________（52） that fuel, first into heat, then energy, some of ____________（53） is used to do work, and some emitted as waste. And ____________（54）.your car uses more energy when the engine is racing than when it is idling, ____________（55） does your body use more energy when you are working hard than ____________（56） you are resting.
        For the purpose of this comparison, ____________（57）, there is one significant difference between them. Your car cannot store fuel by turning it into ____________（58）else ; all gasoline not ____________（ 59） remains as gasoline. But your body stores ____________（60）energy as fat. When the gas tank is ____________（61） empty, the car won't run ; but your body can burn fat to provide more energy.
       Therefore, if you want to gain weight, you must do ____________（62） of two things : eat more calories ( units of heat, therefore energy ) , or use less through ____________（63）. If you want to lose weight, you do the____________（64）, decrease your intake of calories or increase the amount of energy you spend. There is ____________（65）way. Gaining or losing weight is always a relation between intake and output of potential energy.