一旦 yī dàn — in case (sth happens)
yī (first tone, high and level) dàn (fourth tone, falling)yi1 dan4
in case (sth happens)
HSK 5· HSK 1–6 (classic)Level 5· 2021 three-band, nine-level proficiency standardadverbconjunction
Meanings
in case (sth happens)
in case (sth happens); if; once (sth happens; then...); when; in a short time; in one day
adverb