What does 地道 (지도) mean in China?

ANSWER: As a noun, 地道 (지도) can mean either "tunnel" or "causeway," but as an adjective, it means either "authentic," "genuine," or "proper."

By itself, the character 地 (지) can mean "ground," "earth," "land" or "place." And by itself, 道 (도) can mean either "road" or "path." So, together 地道 (지도) literally means "ground (地) road (道)," where "ground" here seems to mean "underground (地下 지하)."

So, in China, I guess the phrase 地道地道 (지도지도) could be translated as "a (一個) real (地道) tunnel (地道)," not a fake one.

By the way, in Taiwan, 地道 (지도) is also used to mean "tunnel," but it is not used to mean "authentic." Instead, in Taiwan, they switch the characters and write 道地 (도지) to mean "authentic."

    

What does the Chinese phrase 開夜車 (개야차) literally mean?

ANSWER: "to drive (開) a night (夜) car (車)"
And what does "to drive a night car" mean in Chinese? It means "to burn the midnight oil" or "to work late into the night."

In the following Taylor Swift (泰勒絲 태륵사) song, the sentence "I stay out too late" was translated into Chinese as 昨晩開了夜車 (작만개료야차), which can literally translate as "Last night (昨晩) [I] drove (開了) a night car (夜車)."