lì / shǐ / kè / shàng / lǎo / shī / xiáng / xì / jiǎng / jiě / le / Bǎi / tuán / Dà / zhàn / de / bèi / jǐng / hé / yǐng / xiǎng

历史课上，老师详细讲解了百团大战的背景和影响。

In history class, the teacher explained the background and impact of the Hundred Regiments Offensive in detail.