每种材料都有记忆,每个行动都会留下痕迹。
真相可能是一把双刃剑,两面都伤人。
Natural gas is a versatile fuel that can support renewable energy growth by providing reliability when the sun isn't shining and the wind isn't blowing.
数学是关于概念之间关系的科学,与这些概念的内容无关。