The Mandarin Chinese phrase '到底 (dàodǐ)' is a question word used for emphasis or to express impatience, urgency, or confusion. The expression is roughly equivalent to the English phrases 'what on earth' or 'what in the world', but it does not necessarily portray a negative consequence. The phrase '到底 (dàodǐ)' is usually used when the speaker wants to stress their question, making it more intensive.