不 vs 沒: Negation
不 for choice and future. 沒 for past facts. The rule is simpler than it looks — until the edge cases.
English has one word for negation: 'not.' Mandarin has two — and they are not interchangeable. 不 covers choices, habits, states, and anything future. 沒 covers past events that didn't happen. Getting them mixed up doesn't produce an accent — it produces a different sentence.
The Core Rule
不 for choice, habit, and future. 沒 for past actions that didn't happen. The rule is stricter than it sounds.
Use 不 to negate something the speaker chooses not to do, habitually doesn't do, or when talking about the present or future.
我不吃肉。
I don't eat meat. — personal choice/habit.
不 is the default negator. When in doubt about whether something is a choice or general state, 不 is usually correct.
Use 沒 (short for 沒有) when a specific action did not occur, or when someone does not have something.
我昨天沒去學校。
I didn't go to school yesterday. — factual, that day.
沒 negates 了 implicitly — you never say 沒了 for past negation because 沒 already cancels completion.
不 in Detail
我不喝酒。
Wǒ bù hē jiǔ.
I don't drink alcohol.
Choice or habit — 不 for something the speaker generally doesn't do.
他明天不來。
Tā míngtiān bù lái.
He's not coming tomorrow.
Future negation always uses 不.
不行！
Bù xíng!
No way! / Not possible!
不 for possibility or acceptability.
我不是老師。
Wǒ bú shì lǎoshī.
I'm not a teacher.
不是 negates identity (X is not Y).
沒 in Detail
我昨天沒去上課。
Wǒ zuótiān méi qù shàngkè.
I didn't go to class yesterday.
Factual past: that day, that action didn't happen.
他還沒回來。
Tā hái méi huí lái.
He hasn't come back yet.
沒 for not-yet-completed expected action.
我沒有錢。
Wǒ méiyǒu qián.
I don't have money.
沒有 for possession negation.
你有沒有看到我的鑰匙？
Nǐ yǒu méiyǒu kàn dào wǒ de yàoshi?
Have you seen my keys?
有沒有 — the standard Taiwanese yes/no question for past actions.
Special Cases
不是 vs 沒有 — don't confuse identity with existence
他沒有是老師。
(ungrammatical)
他不是老師。
He is not a teacher.
不是 negates 是 (X is not Y). 沒有 negates existence or possession (X does not exist / Y does not have X). They are never interchangeable.
Never use 了 with 沒
我昨天沒去了學校。
我昨天沒去學校。
沒 already negates completion. Adding 了 is logically contradictory and grammatically wrong.
習慣 and stative verbs: always 不, never 沒
我沒喜歡她。
我不喜歡她。
沒 is for actions that didn't occur. Emotions and states (喜歡, 知道, 是) use 不. 沒喜歡 sounds like the feeling was never activated — unnatural.
Taiwan & TOCFL Notes
Taiwanese Mandarin uses 有沒有 + verb as the default yes/no question for past actions: 你有沒有吃飯？(Have you eaten?) rather than the Mainland 你吃飯了嗎？Both are correct, but 有沒有 is the more natural form in Taiwan. In casual Taipei speech, 沒有啦 (not at all — soft denial) is used frequently as a polite refusal or modest response where Mainland speakers might say 沒有.
TOCFL Band A tests 不 vs 沒 through short dialogues where the wrong particle changes the sentence from past fact to present habit or vice versa. Band A vocabulary lists include 不是, 沒有, 不能, 不要 as distinct entries. Band B adds the interaction with 有沒有 questions in listening comprehension.
Common Mistakes
Using 不 for past factual negation
我昨天不去學校。
我昨天沒去學校。
Time words (昨天, 上週) signal past — use 沒. 不去 would mean 'I (habitually/by choice) don't go to school' or a future refusal.
Using 沒 for future or modal negation
我明天沒去台北。
我明天不去台北。
Future actions always use 不. 沒 can't negate something that hasn't happened yet.
沒 with stative verbs
我沒知道。
我不知道。
知道, 喜歡, 覺得 describe states, not completed actions. States use 不. 我不知道 (I don't know) is one of the most common sentences in Mandarin — 我沒知道 doesn't exist.
Continue Learning
Referenced Resources
Grammar Hub
All patterns, mapped to Dangdai and TOCFL.
Grammar for Beginners
New to Chinese? Start here — your first 10 patterns in order.
Dangdai Book 1
Where 不 and 沒 are first introduced side by side.
TOCFL Band A Vocabulary
The full word list that tests 不是, 沒有, 不能, 不要.
TOCFL Levels
How Band A and Band B grammar requirements differ.
Negation becomes automatic with the right examples.
Zhong Chinese schedules 不 and 沒 sentences from Dangdai Book 1 using FSRS — so you internalise the distinction through context, not rules.