1 sentence for 历法 (lì​fǎ — calendar system)

1. 在古代，观测五星的运行是制定历法的重要依据。

   zài gǔ​dài, guān​cè wǔ​xīng de yùn​xíng shì zhì​dìng lì​fǎ de zhòng​yào yī​jù.

   In ancient times, observing the movement of the five planets was an important basis for creating calendars.

   Source: Dong Chinese Dictionary