fuel cycle

例句：

1. 1. The engine's fuel cycle is critical for its efficiency.
   发动机的燃料循环对其效率至关重要。
2. 2. The research on the fuel cycle has significant implications for energy conservation.
   对燃料循环的研究对能源节约具有重要意义。
3. 3.The fuel cycle is a complex process that involves the conversion of raw materials into energy.
   燃料循环是一个复杂的过程，涉及将原材料转化为能量。