能量守恒定律是理解许多物理现象的基础。Néngliàng shǒuhéng dìnglǜ shì lǐjiě xǔduō wùlǐ xiànxiàng de jīchǔ.The law of conservation of energy is the basis for understanding many physical phenomena.
这条定律已经被无数次实验证明了。Zhè tiáo dìnglǜ yǐjīng bèi wúshù cì shíyàn zhèngmíng le.This law has been proven by countless experiments.
老师让我们背会这个定律的公式。Lǎoshī ràng wǒmen bèi huì zhège dìnglǜ de gōngshì.The teacher told us to memorise the formula of this law.