一旦
Pinyin: yídàn
in case (sth happens); if; once (sth happens, then...); when
Example sentence
坏习惯一旦被养成，便不能简单地改正。
Huài xíguàn yīdàn bèi yǎngchéng, biàn bù néng jiǎndān de gǎizhèng.
Once you have formed a bad habit, you can't get rid of it easily.
What 一旦 means
一旦 (yídàn) is an Chinese word meaning “in case (sth happens); if; once (sth happens, then...); when”. It appears in the HSK 5 collection.
More HSK 5 words
HSK 5
哎
āi
hey!
哎呀
āiyā
interjection of wonder, shock or admiration
唉
ài
alas; oh dear
爱护
àihù
to cherish; to treasure; to take care of; to love and protect
安
ān
(bound form) calm; peaceful; to calm; to set at ease; to install; to fix; to fit
安全带
ānquándài
seat belt; safety belt
安慰
ānwèi
to comfort; to console
安装
ānzhuāng
to install; to erect; to fix; to mount
暗
àn
dark; to turn dark; secret; hidden; (literary) confused; ignorant
熬夜
áoyè
to stay up late or all night
把握
bǎwò
to grasp (also fig.); assurance; to seize; to hold
白
bái
white; in vain; free of charge; (bound form) vernacular (e.g. 白話|白话[bai2 hua4])