Lì / shǐ / kè / shàng / lǎo / shī / jiè / shào / le / Guì / xì / jūn / fá / de / xīng / shuāi历史课上,老师介绍了桂系军阀的兴衰。In history class, the teacher introduced the rise and fall of the Guangxi warlord faction.