2 sentences for 法则 (fǎ​zé — rule)

1. 数学中有许多重要的运算法则。

   shù​xué zhōng yǒu xǔ​duō zhòng​yào de yùn​suàn fǎ​zé.

   There are many important operational rules in mathematics.

   Source: Dong Chinese Dictionary

2. 在这个多变的时代，很少有永恒不易的法则。

   zài zhè​ge duō​biàn de shí​dài, hěn shǎo yǒu yǒng​héng bù​yì de fǎ​zé.

   In this ever-changing era, few rules remain forever unchanged.

   Source: Dong Chinese Dictionary