"on earth" in Chinese (Traditional)
到底究竟 (語氣加強)
Definition
用於強調疑問句，表示驚訝、困惑或難以置信，比如“這到底是什麼？”這裡不是字面上的地球，而是加強語氣。
Usage Notes (Chinese (Traditional))
'On earth' 多用於口語或書面英語，用來強化問題裡的語氣。通常排在疑問詞（如 what, why, how）之後。正式文章中不建議使用。
Examples
What on earth is that noise?
那到底是什麼聲音？
How on earth did you do that?
你是**到底**怎麼做到的？
Why on earth would you say that?
你**到底**為什麼會那樣說？
Where on earth have you been all day?
你**到底**一整天去哪了？
Who on earth would believe that story?
誰**到底**會相信那個故事？
When on earth are you going to clean your room?
你**到底**什麼時候要打掃房間？