地下 + Noun
地下 (dìxià) means "underground" or "subterranean." It is placed before a noun to describe something located beneath the surface, such as 地下洞穴 (underground cave) or 地下铁 (subway).
这座城市有很大的地下商场。
Zhè zuò chéngshì yǒu hěn dà de dìxià shāngchǎng.
This city has a very large underground shopping mall.
考古队在地下发现了一座古墓。
Kǎogǔ duì zài dìxià fāxiàn le yī zuò gǔmù.
The archaeological team discovered an ancient tomb underground.
地下停车场的入口在大楼的左侧。
Dìxià tíngchēchǎng de rùkǒu zài dàlóu de zuǒcè.
The entrance to the underground parking garage is on the left side of the building.