1、 He joined the underground to fight against the fascists、他參加了地下組織與法西斯作戰。
2、 An underground passage leads to the building across the street、一條地下信道通到街對面的大樓。
3、 Miners work underground、礦工在地下工作。
4、 There is an underground room in the old house、在老房子里有一個(gè)地下室。