Lìshǐ / kè / shàng / lǎoshī / jièshào / le / Wū / huán / yǔ / Zhōngyuán / wángcháo / de / guānxì

历史课上，老师介绍了乌桓与中原王朝的关系。

In history class, the teacher introduced the relationship between the Wuhuan and the Central Plains dynasties.