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 completely empty, the car won’t run; but your body can burn fat to provide more energy.
55().
A.as
B.so
C.why
D.how
cC（g）△H="Q" kJ/mol，其化学平衡常数K和温度的关系如下表所示：
（II）在恒定温度t℃，2L恒容密闭容器中发生反应aA（g）+bB（g） cC（g），容器中A、B、C物质的量变化如图所示，回答下列问题：