BBC 紙片人動畫學英文: The Flatmates 第3集 In the Pub

BBC全文解說及補充資料Episode 3: At the pub
這篇發生在在英國的pub裡，
一群英國人pub喝酒的習慣，會輪流買單，英文的用法如下

to buy a round (v):
                 often when people are in a group, each person takes it in turn to buy drinks for
                 everyone in the group
就一人一輪大家輪流買單的意思。