moving target

剑桥词典

something that moves while someone is trying to hit it
移动的目标
Could you hit a moving target with a football ? 你能把球踢中一个移动中的目标吗？

something that is always changing , making it difficult to count , describe , achieve , etc.
一直在变动的事物（导致难以清点、描述或获得）
The population at risk of hypertension is a moving target . 有高血压风险的人群一直在变化。 返回 moving target