Underpinning
n. 基础材料, 支承结构
✅ 同义词
🗣️ 情景例句
Will it take long?
要很久吗？
Fishing is often frustrating.
钓鱼常常会遭到挫败。
since ground stations and satellites cannot see everywhere.
因为地面工作站和卫星不可能看到地球上的每一个地方。