Lì / shǐ / kè / shàng / lǎo / shī / xiáng / xì / jiǎng / jiě / le / Pái / Huá / fǎ / àn / de / bèi / jǐng

历史课上，老师详细讲解了排华法案的背景。

In history class, the teacher explained the background of the Chinese Exclusion Act in detail.