地铁在地下通行。

Subways run under the ground.

Source: Tatoeba

Sentence Composition

1 地铁 dìtiě
  1. underground railway; subway
  2. subway train
2 在地下 zàidìxià underground
3 通行 tōngxíng
  1. to go through; to pass through
  2. to be in general use