一旦...就(yídàn...jiù)
Once / As Soon As (Permanent)
Structure Pattern
Explanation
一旦...就 (yídàn...jiù) means "once...then." It emphasizes that when a condition occurs (often hypothetical or undesirable), the consequence is significant, lasting, or hard to reverse. Stronger and more serious than 一...就.
Difference from 一...就:
- 一...就: casual, for everyday immediate sequences
- 一旦...就: serious, for significant/irreversible consequences
Example Sentences
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Yídàn cuòguò zhège jīhuì, jiù hěn nán zài yǒu le.
Once you miss this opportunity, it'll be hard to get another.
Yídàn juédìng le, jiù bú yào hòuhuǐ.
Once you decide, don't regret it.
Yídàn yǎngchéng huài xíguàn, jiù hěn nán gǎidiào.
Once you develop a bad habit, it's hard to break.
Common Mistakes
Common Mistake
一旦吃完饭就去散步。
Correct Usage
吃完饭就去散步。
一旦 is reserved for significant, serious, or hard-to-reverse conditions. Using it for routine daily events like finishing a meal sounds overly dramatic. Use 一...就 or simply describe the sequence.
Related Grammar Points
As Soon As / Whenever
yī...jiù
一...就 (yī...jiù) means "as soon as A happens, B follows." It emphasizes the immediate sequence — there's no delay between the two actions. Can also express habitual patterns: "whenever A, then B."
Then / Right Away / As Soon As
jiù
就 (jiù) implies that something happens sooner or more easily than expected. It's the optimistic counterpart to 才 (cái). It can mean "then," "right away," or emphasize that something is simple/quick.
Master 一旦...就
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