A consequence triggered by 一旦
一旦……就……
How it works
一旦 presents a condition as a trigger: once it occurs, the following consequence becomes relevant. 就 often marks the consequence.
The consequence can be a planned response, a prediction, or a general tendency. The pattern does not make every real-world consequence inevitable; context supplies that strength.
The pattern
Example sentences
一旦确定日期，我就通知你。
Once the date is confirmed, I will let you know.
一旦开始，就不要轻易放弃。
Once you start, do not give up easily.
Pinyin generally shows dictionary tones; tones can change in connected speech.
What to watch for
Keep the trigger and its consequence logically connected. 一旦 is not simply a replacement for every occurrence of “if.”
Try it
Use 一旦……就…… to promise to notify someone when a date is confirmed.
Show answer
一旦确定日期，我就通知你。 Yīdàn quèdìng rìqī, wǒ jiù tōngzhī nǐ. Once the date is confirmed, I will let you know.
Syllabus reference
The topic is listed in the official 2025 syllabus. The explanation, examples and practice on this page are written for SenMandarin.
SenMandarin · Updated 2026-10-22