If a story in the news has legs, it will continue for a long time.

未完待续;对某事的后续报道还将持续较长时间

中文中的说法是“留个小尾巴”，表示内容还没有结尾还可以延伸。英语中“尾巴”就变成了“腿”，也就是have legs，就表示故事还没结束还会继续。

This latest scandal has legs - you'll probably still be reading about it in a year's time.

最近的丑闻还有下文。也许近一年内，你还会读到其后续报道。