词源趣谈 | sell someone down the river（在紧要关头） 抛弃，出卖

sell someone down the river 指背叛、出卖。比如：

• He has been sold down the river by the people who were supposed to protect him.
  他被那些本应该保护他的人出卖了。

该短语可追溯到 19世纪30年代，当时的美洲奴隶主为了惩罚奴隶而将他们卖到密西西比河下游的甘蔗种植园，那里环境极端恶劣。

后来，人们用该短语表示“为了个人利益而出卖他人”之意。