For autodidact students of Mandarin, the negation particle 不 (bù) — "not" — is one of the most fundamental words in the language. It negates verbs, adjectives, and modal verbs. However, it has a crucial restriction: it cannot negate 有 (yǒu, to have) or express past negation of completed actions — those functions belong to 没 (méi). Mastering when to use 不 versus 没 is one of the first major grammatical distinctions a Mandarin learner must make.
FAQ: What does 不 (bù) mean in Mandarin? 不 is the general negation particle meaning "not." It negates most verbs (不去 not go, 不吃 not eat), adjectives (不好 not good, 不大 not big), and modal verbs (不能 cannot, 不应该 should not). It expresses present/habitual or future negation. The separate particle 没 (méi) is used to negate 有 (have) and to negate past completed actions.
Key Takeaways: - 不 negates: verbs, adjectives, modals — present/habitual/future contexts - 没 negates: 有 (have), and past completed actions (instead of 不 + 了) - Tonal sandhi: 不 is 4th tone normally; before another 4th-tone word it becomes 2nd: 不是 búshì, 不去 bú qù - Double negation: 不…不 = neither…nor; 不能不 = cannot but / must
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The character 不 is thought to be a pictograph of a bird flying upward (unable to be grasped) or of a plant root growing downward (unable to reach something above). As a high-frequency character, it is written with four strokes: horizontal, two strokes forming a cross, then a falling stroke.
Tonal sandhi — the tone change rule: When 不 (bù, 4th tone) precedes a 4th-tone syllable, it changes to 2nd tone: 不是 → búshì (not is), 不去 → bú qù (not go), 不对 → bú duì (not right). Before other tones, 不 remains bù.
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20.1a 我 I 不 not 喝 drink 咖啡 coffee
20.1b (wǒ) I (bù) not (hē) drink (kāfēi) coffee
20.2a 他 he 不 not 是 is 老师 teacher ， , 是 is 医生 doctor
20.2b (tā) he (bù) not (shì) is (lǎoshī) teacher (shì) is (yīshēng) doctor
20.3a 这里 here 不 not 冷 cold ， , 很 very 舒服 comfortable
20.3b (zhèlǐ) here (bù) not (lěng) cold (hěn) very (shūfu) comfortable
20.4a 我 I 明天 tomorrow 不 not 去 go 上班 work
20.4b (wǒ) I (míngtiān) tomorrow (bù) not (qù) go (shàngbān) work
20.5a 她 she 不 not 会 can 说 speak 英语 English
20.5b (tā) she (bù) not (huì) can (shuō) speak (Yīngyǔ) English
20.6a 你 you 为什么 why 不 not 吃 eat 呢 PART ؟
20.6b (nǐ) you (wèishénme) why (bù) not (chī) eat (ne) PART ?
20.7a 这 this 件 CL 事 matter 不 not 简单 simple
20.7b (zhè) this (jiàn) CL (shì) matter (bù) not (jiǎndān) simple
20.8a 不 not 好 good 意思 meaning ， , 我 I 来 come 晚 late 了 PERF
20.8b (bù) not (hǎo) good (yìsi) meaning (wǒ) I (lái) come (wǎn) late (le) PERF [= Sorry, I'm late]
20.9a 他 he 不 not 但 only 聪明 smart ， , 而且 moreover 勤奋 hardworking
20.9b (tā) he (bù) not (dàn) only (cōngming) smart (érqiě) moreover (qínfèn) hardworking
20.10a 这 this 种 CL 食物 food 我 I 没 not [PAST] 吃过 eaten [EXP]
20.10b (zhè) this (zhǒng) CL (shíwù) food (wǒ) I (méi) not [PAST] (chī guo) eaten [EXP]
20.11a 我 I 的 DE 钱包 wallet 里 inside 没 not [PAST] 有 have 钱 money 了 PERF
20.11b (wǒ) I (de) DE (qiánbāo) wallet (lǐ) inside (méi) not [PAST] (yǒu) have (qián) money (le) PERF
20.12a 不 not 行 work/acceptable ， , 这 this 样 way 做 do 不 not 对 right
20.12b (bù) not (xíng) work/acceptable (zhè) this (yàng) way (zuò) do (bù) not (duì) right
20.13a 他 he 不 not 能 can 不 not 来 come ， , 这 this 是 is 规定 rule
20.13b (tā) he (bù) not (néng) can (bù) not (lái) come (zhè) this (shì) is (guīdìng) rule [= He cannot but come]
20.14a 你 you 不 not 累 tired 吗 Q ？ ?
20.14b (nǐ) you (bù) not (lèi) tired (ma) Q ?
20.15a 不 not 学 study 不 not 知道 know ， , 一 once 学 study 吓一跳 shocked
20.15b (bù) not (xué) study (bù) not (zhīdào) know (yī) once (xué) study (xià yī tiào) shocked [= Until you study it you don't know; once you do — what a shock!]
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20.1 我不喝咖啡。 "I don't drink coffee." 20.2 他不是老师，是医生。 "He is not a teacher; he is a doctor." 20.3 这里不冷，很舒服。 "It's not cold here; it's very comfortable." 20.4 我明天不去上班。 "I'm not going to work tomorrow." 20.5 她不会说英语。 "She can't speak English." 20.6 你为什么不吃呢？ "Why aren't you eating?" 20.7 这件事不简单。 "This matter is not simple." 20.8 不好意思，我来晚了。 "Sorry, I'm late." 20.9 他不但聪明，而且勤奋。 "He is not only smart but also hardworking." 20.10 这种食物我没吃过。 "I have never eaten this kind of food." 20.11 我的钱包里没有钱了。 "There is no money left in my wallet." 20.12 不行，这样做不对。 "No good — doing it this way is not right." 20.13 他不能不来，这是规定。 "He cannot but come — it is the rule." 20.14 你不累吗？ "Aren't you tired?" 20.15 不学不知道，一学吓一跳。 "Until you study it you don't know; once you study — what a shock!"
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20.1 我不喝咖啡。 20.2 他不是老师，是医生。 20.3 这里不冷，很舒服。 20.4 我明天不去上班。 20.5 她不会说英语。 20.6 你为什么不吃呢？ 20.7 这件事不简单。 20.8 不好意思，我来晚了。 20.9 他不但聪明，而且勤奋。 20.10 这种食物我没吃过。 20.11 我的钱包里没有钱了。 20.12 不行，这样做不对。 20.13 他不能不来，这是规定。 20.14 你不累吗？ 20.15 不学不知道，一学吓一跳。
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These are the grammar rules for 不 (bù) — "not":
不 versus 没 — the fundamental distinction:
不 (bù): negates habitual, present, and future actions and states. It expresses will, habit, ability (with modals), or description. - 我不吃鱼 (I don't eat fish — habit) - 她不会游泳 (She can't swim — ability) - 明天我不去 (Tomorrow I'm not going — future)
没/没有 (méi/méiyǒu): negates completed past actions and the verb 有 (to have). - 我没吃鱼 (I didn't eat fish — past event) - 他没有钱 (He doesn't have money — have) - 我没去 (I didn't go — past)
Tonal sandhi: 不 is 4th tone (bù) but changes to 2nd tone (bú) before another 4th-tone syllable: - 不是 → búshì | 不去 → bú qù | 不对 → bú duì | 不会 → bú huì (hui is 4th tone)
Fixed phrases with 不: - 不好意思 (bù hǎoyìsi): "sorry / excuse me" — literally "not good meaning" - 不行 (bù xíng): "no good / not acceptable / won't work" - 不但…而且 (bùdàn…érqiě): "not only…but also" — a common paired conjunction - 不能不 (bù néng bù): double negation = "cannot but / must" — 他不能不来 (He must come)
Common Mistakes: - Using 不 to negate completed past actions: *我不吃了 (wrong) — should be 我没吃 - Using 不 to negate 有: *我不有钱 (wrong) — should be 我没有钱 - Forgetting tonal sandhi — not grammatically wrong but sounds unnatural
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不 appears in some of the most common social phrases in Chinese. 不好意思 (excuse me/sorry) is used constantly — for small inconveniences, for modesty, for declining. 不客气 (you're welcome, bú kèqi) literally means "not polite/formal," expressing that thanks are unnecessary between friends. 不要紧 (it doesn't matter, bú yàojǐn) smooths over minor problems.
The pattern 不…不 (neither…nor) is found throughout classical Chinese aphorisms: 不鸣则已，一鸣惊人 (If it doesn't call, nothing; once it calls, it shocks the world — a proverb about silent preparation and sudden achievement).
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《论语·为政》第十七章 — Analects, Book 2, Chapter 17
知之为知之，不知为不知，是知也。
F-A: Interlinear Construed Text
知 (zhī) know 之 (zhī) it [OBJ-CL] 为 (wéi) is [CL] 知 (zhī) know 之 (zhī) it ， , 不 (bù) not 知 (zhī) know 为 (wéi) is [CL] 不 (bù) not 知 (zhī) know ， , 是 (shì) this 知 (zhī) wisdom 也 (yě) PART
F-B: Text with Translation
知之为知之，不知为不知，是知也。
"To know what you know and to know what you do not know — this is knowledge."
F-C: Authentic Text Only
知之为知之，不知为不知，是知也。
F-D: Grammar Notes
不知 (bù zhī): classical "not know" — in classical Chinese, 不 negates 知 directly without a separate object pronoun. In modern Chinese: 不知道 (bù zhīdào).
为 (wéi): classical copula "is/to be" — distinct from modern 是 (shì). Here: "to acknowledge it as" = to call it / to treat it as.
是知也 (shì zhī yě): "this is wisdom/knowledge" — 是 (this/this is), 知 (wisdom/knowledge), 也 (classical sentence-final affirmation particle). The character 知 here means both "to know" and "wisdom" — a pun that makes the aphorism circular and elegant.
F-E: Literary Commentary
This saying of Confucius is a masterpiece of concision. It uses 不 four times — 不知为不知 — and each negation is a positive claim: admitting what you don't know IS knowledge. The lesson word 不 is here not merely a grammatical particle but the epistemological foundation of Confucian intellectual humility. To say 不 honestly — "I do not know" — is the beginning of wisdom.
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Two colleagues, Zhang Ming and Li Hua, debate a work decision. The dialogue runs through 不 across all its functions — disagreement, negation of past actions, modals, fixed phrases — while showing natural Chinese conversational register.
20.16a 张明 Zhang-Ming 说 say ： : "这 this 个 CL 方案 plan 不 not 好 good ， , 我 I 不 not 同意 agree 。"
20.16b (Zhāng Míng) Zhang-Ming (shuō) say (zhè) this (gè) CL (fāng'àn) plan (bù) not (hǎo) good (wǒ) I (bù) not (tóngyì) agree
20.17a 李华 Li-Hua 问 ask ： : "你 you 为什么 why 不 not 同意 agree 呢 PART ؟"**
20.17b (Lǐ Huá) Li-Hua (wèn) ask (nǐ) you (wèishénme) why (bù) not (tóngyì) agree (ne) PART ?
20.18a "这 this 个 CL 预算 budget 不 not 够 enough ， , 而且 moreover 时间 time 也 also 不 not 够 enough 。"
20.18b (zhè) this (gè) CL (yùsuàn) budget (bù) not (gòu) enough (érqiě) moreover (shíjiān) time (yě) also (bù) not (gòu) enough
20.19a "我们 we 没 not [PAST] 有 have 足够 sufficient 的 DE 数据 data 来 to 支持 support 这 this 个 CL 决定 decision 。"
20.19b (wǒmen) we (méi) not [PAST] (yǒu) have (zúgòu) sufficient (de) DE (shùjù) data (lái) to (zhīchí) support (zhè) this (gè) CL (juédìng) decision
20.20a 李华 Li-Hua 说 say ： : "不 not 是 is 没有 not-have 数据 data ， , 是 is 你 you 没有 not-have 看 look 到 to 。"
20.20b (Lǐ Huá) Li-Hua (shuō) say (bù) not (shì) is (méiyǒu) not-have (shùjù) data (shì) is (nǐ) you (méiyǒu) not-have (kàn) look (dào) to
20.21a 张明 Zhang-Ming 不 not 服气 convinced ： : "你 you 不 not 能 can 这样 like-this 说 say 我 me 。"
20.21b (Zhāng Míng) Zhang-Ming (bù) not (fúqì) convinced (nǐ) you (bù) not (néng) can (zhèyàng) like-this (shuō) say (wǒ) me
20.22a "我 I 不 not 是 is 批评 criticise 你 you ， , 我 I 是 is 说 say 事实 facts 。"
20.22b (wǒ) I (bù) not (shì) is (pīpíng) criticise (nǐ) you (wǒ) I (shì) is (shuō) say (shìshí) facts
20.23a 两人 two-people 争 argue 了 PERF 很久 long-time ， , 都 both 不 not 让步 concede
20.23b (liǎng rén) two-people (zhēng) argue (le) PERF (hěn jiǔ) long-time (dōu) both (bù) not (ràngbù) concede
20.24a 主管 supervisor 进 enter 来 come 说 say ： : "行 OK 了 PERF ， , 不 not 要 want 吵 argue 了 PERF 。"
20.24b (zhǔguǎn) supervisor (jìn) enter (lái) come (shuō) say (xíng le) OK (bù) not (yào) want (chǎo) argue (le) PERF
20.25a "这 this 个 CL 问题 problem 不 not 是 is 非此即彼 either-or 的 DE ， , 可以 can 找 find 中间 middle 方案 plan 。"
20.25b (zhè) this (gè) CL (wèntí) problem (bù) not (shì) is (fēi cǐ jí bǐ) either-or (de) DE (kěyǐ) can (zhǎo) find (zhōngjiān) middle (fāng'àn) plan
20.26a 张明 Zhang-Ming 和 and 李华 Li-Hua 都 both 不 not 说 say 话 words 了 PERF
20.26b (Zhāng Míng) Zhang-Ming (hé) and (Lǐ Huá) Li-Hua (dōu) both (bù) not (shuō) say (huà) words (le) PERF
20.27a 主管 supervisor 继续 continue 说 say ： : "不 not 是 is 谁 who 对 right 谁 who 错 wrong ， , 是 is 目标 goal 对 right 不 not 对 right 。"
20.27b (zhǔguǎn) supervisor (jìxù) continue (shuō) say (bù) not (shì) is (shéi) who (duì) right (shéi) who (cuò) wrong (shì) is (mùbiāo) goal (duì) right (bù) not (duì) right
20.28a 他们 they 都 both 想了 think-PERF 想 think ， , 点 nod 了 PERF 头 head
20.28b (tāmen) they (dōu) both (xiǎng le) think-PERF (xiǎng) think (diǎn) nod (le) PERF (tóu) head
20.29a 张明 Zhang-Ming 说 say ： : "不 not 好意思 good-meaning ， , 我 I 刚才 just-now 说话 speak 不 not 注意 careful 了 PERF 。"
20.29b (Zhāng Míng) Zhang-Ming (shuō) say (bù) not (hǎoyìsi) good-meaning (wǒ) I (gāngcái) just-now (shuōhuà) speak (bù) not (zhùyì) careful (le) PERF
20.30a 他们 they 最终 finally 达成 reach 了 PERF 一个 one-CL 两人 both 都 both 不 not 太满意 too-satisfied 、 , 但 but 都 both 不 not 反对 oppose 的 DE 方案 plan
20.30b (tāmen) they (zuìzhōng) finally (dáchéng) reach (le) PERF (yī gè) one-CL (liǎng rén) both (dōu) both (bù) not (tài mǎnyì) too-satisfied (dàn) but (dōu) both (bù) not (fǎnduì) oppose (de) DE (fāng'àn) plan
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20.16 张明说："这个方案不好，我不同意。" "Zhang Ming said: 'This plan is no good; I don't agree.'" 20.17 李华问："你为什么不同意呢？" "Li Hua asked: 'Why don't you agree?'" 20.18 "这个预算不够，而且时间也不够。" "'The budget isn't enough, and neither is the time.'" 20.19 "我们没有足够的数据来支持这个决定。" "'We don't have sufficient data to support this decision.'" 20.20 李华说："不是没有数据，是你没有看到。" "Li Hua said: 'It's not that there's no data — it's that you haven't seen it.'" 20.21 张明不服气："你不能这样说我。" "Zhang Ming was not convinced: 'You can't talk about me like that.'" 20.22 "我不是批评你，我是说事实。" "'I'm not criticising you; I'm stating facts.'" 20.23 两人争了很久，都不让步。 "The two argued for a long time, neither conceding." 20.24 主管进来说："行了，不要吵了。" "The supervisor came in and said: 'Alright, stop arguing.'" 20.25 "这个问题不是非此即彼的，可以找中间方案。" "'This problem is not either-or; a middle ground can be found.'" 20.26 张明和李华都不说话了。 "Zhang Ming and Li Hua both fell silent." 20.27 主管继续说："不是谁对谁错，是目标对不对。" "The supervisor continued: 'It's not about who's right or wrong — it's about whether the goal is right.'" 20.28 他们都想了想，点了头。 "They both thought for a moment and nodded." 20.29 张明说："不好意思，我刚才说话不注意了。" "Zhang Ming said: 'Sorry, I wasn't being careful in what I said just now.'" 20.30 他们最终达成了一个两人都不太满意、但都不反对的方案。 "They finally reached a plan that neither was entirely satisfied with, but neither opposed."
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20.16 张明说："这个方案不好，我不同意。" 20.17 李华问："你为什么不同意呢？" 20.18 "这个预算不够，而且时间也不够。" 20.19 "我们没有足够的数据来支持这个决定。" 20.20 李华说："不是没有数据，是你没有看到。" 20.21 张明不服气："你不能这样说我。" 20.22 "我不是批评你，我是说事实。" 20.23 两人争了很久，都不让步。 20.24 主管进来说："行了，不要吵了。" 20.25 "这个问题不是非此即彼的，可以找中间方案。" 20.26 张明和李华都不说话了。 20.27 主管继续说："不是谁对谁错，是目标对不对。" 20.28 他们都想了想，点了头。 20.29 张明说："不好意思，我刚才说话不注意了。" 20.30 他们最终达成了一个两人都不太满意、但都不反对的方案。
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不是…是 (bùshì…shì) — correction construction: 不是没有数据，是你没有看到 — "It's not that there's no data; it's that you haven't seen it." This pattern corrects a mistaken assumption: 不是 (it is not the case that) + [wrong version] + ，+ 是 (it is) + [correct version]. Essential for clarification and argument.
不要 (bù yào): "don't" — the negated imperative. 不要吵了 = "stop arguing." 不要 negates the volitional verb 要 and functions as a prohibition. More emphatic than just 不.
想了想 (xiǎng le xiǎng): reduplicated verb with 了 between — expresses a brief repetition of an action: "thought for a moment." This reduplication pattern (V + 了 + V) is common for short, tentative actions: 试了试 (gave it a try), 看了看 (had a look).
不…不反对 (bù…bù fǎnduì): the complex final sentence constructs a nuanced negative: "not too satisfied, but also not opposed." The two negations (都不太满意…都不反对) create a diplomatic middle ground — the typical Chinese compromise register.
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不 (bù / bú) — IPA: /pu˥˩/ (4th tone) or /pu˧˥/ (2nd tone before 4th-tone syllable)
- b: bilabial unaspirated stop [p] — Chinese b is unaspirated and slightly voiced. English "b" has more voice; English "p" has aspiration. Chinese b is between them. - ù: high back rounded vowel [u] — like English "oo" in "boot" - Tone sandhi: bù (4th) → bú (2nd) before another 4th-tone syllable
Practise the tonal sandhi: - 不是 búshì | 不对 bú duì | 不去 bú qù | 不会 bú huì - 不好 bù hǎo | 不来 bù lái | 不吃 bù chī (no change before 1st/2nd/3rd tone)
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