形容词 on-the-scene:

1. at the scene of action

onprep.在 ... 之上；由 ... 支撑着；在（某一天）；关于；基于adv.穿着；向前（移动)；表示持续性adj.表示已连接、处于工作状态或使用中；发生；值班Onurlu奥努尔卢

1. There are enemy aircraft on the radar screen.
   雷达萤屏上出现了敌人的飞机。
2. The mighty iceberg came into view.
   巨大的冰山出现在眼前。
3. All the best bonnets of the city were there.
   城里戴最漂亮的无边女帽的妇女全都到场了。
4. He showed up after the party was over.
   晚会结束后他才到场。