一旦

Pattern visualization

Examples

1. 一旦做出决定,就不要轻易改变。▶ —
   Once you make a decision, don’t change it easily.
2. 机会一旦错过,就很难再有。▶ —
   Once an opportunity is missed, it is hard to get again.

Collocations

Mnemonic

一 yī "one" + 旦 dàn "dawn": in a single morning; "once, in case". ① once something happens (condition, often 一旦 … 就 …) ② all at once. Contrast 万一: 一旦 supposes the event then follows it through, 万一 is a slim-chance precaution.

Related

Quick check

1. What is the difference between 一旦 and 万一?

   • 一旦 = once it happens (then …); 万一 = a slim-chance precaution
   • identical
   • 一旦 = color; 万一 = taste
   • 万一 = past only