About
HSK levels

    一旦

    yīdàn

    1. in case (sth happens); if; once (sth happens, then...)
    2. when
    3. in a short time; in one day

    一旦你决定了,就要坚持下去。 yīdàn nǐ juédìngle, jiù yào jiānchí xiàqù.