How to Say “Act Now or Else” with 再不……就…… (zàibù... jiù...)
再不……就…… (zàibù... jiù...) is the “act now or else” warning: (Subject +) 再不 + the action needed now, 就 + the bad thing about to happen, usually closed with 了 (你再不走，就迟到了, “if you don't leave now, you'll be late”). It carries built-in urgency. Don't confuse it with 再也不 (“never again”) or 不再 (“no longer”), which look similar but do completely different jobs.
Why this trips learners up
再不……就…… (zàibù... jiù...) is the pattern for pressing someone to act before it's too late: “if you don't do this now, then something bad is about to happen.” 你再不走，就迟到了 (“if you don't leave now, you'll be late”), 火车再不检票就来不及了 (“if we don't get our tickets checked now, we won't make it”). Even without the word 现在 (“now”), the whole frame carries an implied “now,” a real sense of the clock running out.
The structure is two clauses: (Subject +) 再不 + Action, 就 + Consequence (+ 了). What comes right after 再不 is the action the person needs to take immediately; what comes after 就 is the dire result that follows if they don't. 你再不努力，就会被淘汰了 (“if you don't start working hard, you'll get eliminated”). The consequence clause almost always ends in 了, because it marks an imminent change, something on the verge of happening: 菜再不吃就凉了 (“eat now or the food will go cold”). Mechanically it's nothing more than the “any longer” 再 plus negation 不 plus the “then” 就, but the combination rarely comes to mind on its own, so it's worth drilling as a single unit.
Now the part that trips learners up, and the reason this page leans on the comparison below: 再不 looks almost identical to two other expressions it has nothing to do with. The first is 再也不 (zài yě bù), “never again,” a firm resolution not to repeat something: 我再也不迟到了 (“I'll never be late again”). That's a statement about the future, not a threat, and it doesn't take 就. The second is 不再 (bú zài), the reverse order, meaning “no longer / not anymore”: 他不再联系我了 (“he no longer contacts me”). Same three characters in play, three completely different meanings.
So keep the jobs apart. 再不……就…… is a conditional warning about a looming consequence, “act now or else” (你再不打电话，就失去这个机会了). 再也不 is a permanent “never again.” 不再 is a plain “no longer.” If your sentence has a 就 clause and a deadline breathing down its neck, you want 再不……就……; if you're vowing never to do something again, it's 再也不; if you're simply saying something has stopped, it's 不再.
The structure
Colour key
Each colour marks one grammatical role — and the same colour means the same role on every page in the Lab.
Examples in context
Real-world sentences, easiest first. Toggle pinyin or the translation, tap any word to see its role, or play the audio.
Tap a word to see its grammatical role.
nǐ 你 Subject zài 再 Pattern bù 不 Negation chī 吃， Verb cài 菜 Subject jiù 就 Pattern liáng le 凉了 Other
If you don't eat now, the food will get cold (everyday 再不…就…了 warning).
zài 再 Pattern bù 不 Negation chūfā 出发， Verb wǒmen 我们 Subject jiù 就 Pattern gǎnbushàng huǒchē le 赶不上火车了 Other
If we don't set off now, we'll miss the train (subject dropped in clause 1, its own subject in clause 2).
nǐ 你 Subject zài 再 Pattern bù 不 Negation huí xiāoxi 回消息， Verb wǒ 我 Subject jiù 就 Pattern xiān zǒu le 先走了 Other
If you don't reply, I'm leaving first (the speaker's own threatened reaction as the consequence).
zài 再 Pattern bú 不 Negation dìng piào 订票， Verb hǎo zuòwèi 好座位 Subject jiù 就 Pattern mài wán le 卖完了 Other
If you don't book now, the good seats will be sold out (不 before a 4th-tone verb → bú).
nǐ 你 Subject zài 再 Pattern bú 不 Negation qù kàn yīshēng 去看医生， Verb bìng 病 Subject jiù 就 Pattern gèng yánzhòng le 更严重了 Other
If you don't go see a doctor, your illness will only get worse (consequence is a worsening state).
tiān 天 Subject zài 再 Pattern bú 不 Negation xià yǔ 下雨， Verb zhuāngjia 庄稼 Subject jiù 就 Pattern yào hàn sǐ le 要旱死了 Other
If it doesn't rain soon, the crops are going to die of drought (non-human subject, 就要…了).
rúguǒ 如果 Connector nǐ 你 Subject zài 再 Pattern bú 不 Negation zuò juédìng 做决定， Verb jīhuì 机会 Subject jiù 就 Pattern méi le 没了 Other
If you still don't make a decision, the chance will be gone (explicit 如果 fronting the whole conditional).
wǒ 我 Subject zài 再 Pattern bù 不 Negation jiǎnféi 减肥， Verb zhèxiē kùzi 这些裤子 Subject jiù 就 Pattern dōu chuān bu xià le 都穿不下了 Other
If I don't lose weight, none of these trousers are going to fit (self-directed, with a potential complement).
Common mistakes
Why it happens: 再不……就…… is not 再也不. 再也不 means “never again,” a resolution about the future (我再也不迟到了), and it doesn't fit an “act now or else” warning or take a 就 clause. For the urgency conditional, it's 你再不走就迟到了, with 再不 (“if you still don't”), not 再也不.
Why it happens: The consequence clause marks an imminent change, so it almost always ends in 了. 你再不吃，菜就凉了 (“the food's about to go cold”) needs that 了; 菜就凉 without it sounds unfinished and loses the “on the verge of happening” force. Keep the 了 on the result.
Why it happens: 再不 and 不再 are not interchangeable, the word order flips the meaning. 再不 means “if you still don't” and drives the warning (你再不走，我就叫人了); 不再 means “no longer / not anymore” (他不再联系我了), a different statement entirely. For “act now or else,” it must be 再不.
Compare & contrast
| 再不……就…… zàibù... jiù... (an urgent “if still not X, then bad Y is about to happen”) | 再也不 zài yě bù (a flat “never again,” a resolution not to repeat something) | The difference |
|---|---|---|
| 你再不走就迟到了nǐ zài bù zǒu jiù chídào le = “if you don’t leave now, you’ll be late” (再不…就…: an urgent warning, “if still not X, then bad Y is about to happen”) | 我再也不迟到了wǒ zài yě bù chídào le = “I’ll never be late again” (再也不: a firm resolution never to repeat something) | 你再不走就迟到了 means “if you don't leave now, you'll be late,” 再不…就… giving an urgent warning about a looming consequence. 我再也不迟到了 means “I'll never be late again,” 再也不 stating a firm resolution never to repeat something. They share 再…不 but do opposite jobs: one warns, the other vows. |
| 菜再不吃就凉了cài zài bù chī jiù liáng le = “eat now or the food will go cold” (再不…就…: always paired with 就, pointing at a looming consequence) | 他再也不来了tā zài yě bù lái le = “he won’t ever come again” (再也不: stands alone, negating any future recurrence) | 菜再不吃就凉了 means “eat now or the food will go cold,” 再不…就… always leaning on 就 to point at what's about to happen. 他再也不来了 means “he won't ever come again,” 再也不 standing alone to negate any future recurrence. One is a conditional threat with a deadline; the other a permanent “never again.” |
Try it yourself
Say “If you still don't tell me, I'm going to get angry.” Use 再不 + action, 就 + consequence.
Related patterns
Quick reference card
How to Say “Act Now or Else” with 再不……就…… (zàibù... jiù...) grammar.merrymandarin.com A pocket summary — print it and keep it by your desk.