which came first, the chicken or the egg?the chicken or the egg? which came first NOT KNOWused to say that it is difficult or impossible to decide which of two things happened first, or which action is the cause and which is the effect 先有鸡，还是先有蛋？〔用于表示先后或因果难以区分〕 → which came first, the chicken or the egg? at chicken1(1)