南朝梁国刘勰在《文心雕龙·附会》篇里谈到写文章必须外文、内义配合得当，一如马匹“并驾齐驱”。人们后来就用这“并驾齐驱”四字来说“不相上下”了。英文也有一个类似的成语:neck and neck(颈并颈)。这成语同样是出自跑马。在赛马场上，马匹凭一个颈位之差取胜，叫做The horse wins by a neck。假如两匹马neck and neck，那就是“并驾齐驱”的意思了。这成语可以引伸来指种种激烈的竞争，例如:A poll taken shortly before the election showed that the two presidential candidates were still neck and neck(选举前不久的民意调查显示，两名总统候选人依然是势均力敌)。Neck and neck三字之间加上连字号(hyphen)，可作形容词用，例如:It was an neck-and-neck competition(那场比赛旗鼓相当)。