moving target
noun [ C ] uk/ˌmuː.vɪŋ ˈtɑːr.ɡɪt/ us/ˌmuː.vɪŋ ˈtɑːr.ɡɪt/
移动的目标
something that moves while someone is trying to hit it
Could you hit a moving target with a football? 你能把球踢中一个移动中的目标吗？
一直在变动的事物（导致难以清点、描述或获得）
something that is always changing, making it difficult to count, describe, achieve, etc.
The population at risk of hypertension is a moving target. 有高血压风险的人群一直在变化。