lì / shǐ / kè / shàng / lǎo / shī / jiè / shào / le / yǎn / cài / zhè / ge / gǔ / dài / yóu / mù / mín / zú

历史课上，老师介绍了奄蔡这个古代游牧民族。

In history class, the teacher introduced the ancient nomadic people known as the Alans.