1. If you give up exercise, your muscles shrink and fat increases. By the same token, if you expend more energy you will lose fat. 如果你放弃锻炼，肌肉就会萎缩，脂肪会增多。同样地，如果你消耗较多的体能，你就会减掉脂肪。
2. Growth, reproduction, and daily metabolism all require an organism to expend energy. 生长、繁殖和日常的新陈代谢都需要有机体来消耗能量。
3. Extreme athletes expend lots of energy breaking down and repairing and building muscles. 极限运动员消耗大量能量来分解、修复和塑造肌肉。
4. Since 1914, scientists have known that birds flying in formation—a V-shape—expend less energy. 自1914年以来，科学家们已经知道，以V字形队形飞行的鸟类消耗的能量更少。
5. Why does their behavior indicate more of a concern with how much energy they expend than with being exposed to predators? 为什么它们的行为表明它们更关心的是消耗多少能量而不是担心暴露在捕食者面前呢？
