"Underground" 是英语中用来形容地底的词，可以用来描述地下空间、地下建筑、地下设施、地下交通等。例如：
The underground parking garage was full, so I had to park on the street. (地下停车场已经满了，所以我只能停在街上。)
There is an underground network of tunnels that connects the different buildings on campus. (校园里有一个地下隧道网络，连接着不同的建筑。)
The underground river was discovered by accident while they were drilpng for oil. (他们在钻油的时候意外发现了这条地下河。)
"Underground" 这个词源于拉丁语 "subterraneus"，意思是 "在地下的"。它是由 "sub-" 和 "terra" 两个词组成的，"sub-" 表示 "在下面"，"terra" 是拉丁语中的 "地"。
The underground parking garage was full, so I had to park on the street. (地下停车场已经满了，所以我只能停在街上。)
There is an underground network of tunnels that connects the different buildings on campus. (校园里有一个地下隧道网络，连接着不同的建筑。)
The underground river was discovered by accident while they were drilpng for oil. (他们在钻油的时候意外发现了这条地下河。)
"Underground" 这个词源于拉丁语 "subterraneus"，意思是 "在地下的"。它是由 "sub-" 和 "terra" 两个词组成的，"sub-" 表示 "在下面"，"terra" 是拉丁语中的 "地"。