terrain clearance altitude

例句：

1. 1.The team needs to clear the terrain for the next mission.
   团队需要为下一个任务清除地形。
2. 2.The climber cleared the terrain and reached the summit.
   登山者清除了地形并到达了山顶。
3. 3. The aircraft was cleared for takeoff at a terrain clearance altitude of 500 feet.
   飞机在500英尺的地形清除高度被批准起飞。