HSK 6 grammar · pattern
不X不…，一X…
不X不…，一X就… — won't … unless; the moment X …
Pattern
+ + + + + +
( ) can be left out · other words may come before, between and after
How it works
This spoken frame contrasts refusal without a trigger against instant action once the trigger comes — "won't … unless X; the moment X, then …". It highlights how someone acts only on cue.
Examples
这孩子不问不说，一问就全说了。
Zhè háizi bú wèn bù shuō, yí wèn jiù quán shuō le.
This child won't talk unless asked, but the moment you ask, he tells everything.
他不催不动，一催就快了。
Tā bù cuī bú dòng, yì cuī jiù kuài le.
He won't budge unless pushed; push him and he speeds up.
机器不修不转，一修就好了。
Jīqì bù xiū bú zhuàn, yì xiū jiù hǎo le.
The machine won't run unless repaired; fix it and it works.
Related
See it in a story
In the app, 不X不…，一X… is underlined wherever it appears in the stories you read, and practised with sentences from them. Free.