lì shǐ / kè shàng / lǎo shī / jiè shào / le / Bā guó Lián jūn / rù qīn / Běi jīng / de / jīng guò

历史课上，老师介绍了八国联军入侵北京的经过。

In history class, the teacher explained the course of the Eight-Nation Alliance's invasion of Beijing.