energy theorem

例句：

1. 1. The energy theorem states that the total energy in a closed system remains constant.
   能量守恒定律表明，封闭系统的能量总量保持不变。
2. 2. In thermodynamics, the law of conservation of energy is fundamental to understanding the behavior of matter and energy.
   在热力学中，能量守恒定律是理解物质和能量行为的基础。
3. 3. The principle of energy conservation is crucial for designing efficient energy-using systems.
   能量守恒原理对于设计高效的能源利用系统至关重要。