zài / huà / xué / shí / yàn / kè / shàng / lǎo / shī / yǎn / shì / le / sè / pǔ / fǎ / de / jī / běn / yuán / lǐ在化学实验课上,老师演示了色谱法的基本原理。In chemistry class, the teacher demonstrated the basic principles of chromatography.