lì / shǐ / kè / shàng / lǎo / shī / xiáng / xì / jiǎng / jiě / le / Hóng / sè / Gāo / mián / de / xiāng / guān / shǐ / shí

历史课上老师详细讲解了红色高棉的相关史实。

The history teacher explained the historical facts related to the Khmer Rouge in detail.