be an item 的本意是一个项目，它的寓意是一对恋人，恋爱关系。

【例句】
Andy and Becky met at a club and almost immediately became an item. Last week they decided to get married. Everything happened in a rush for them.
安迪和贝基在一家俱乐部相遇，几乎立刻成了一对恋人。上周他们决定结婚。对他们来说，一切都发生得很匆忙。

John and Sally are frequently seen together nowadays. Are they an item?
约翰和莎莉现在经常在一起。他们在谈恋爱吗？