Comparing "bu" and "mei"

Both 不 (bù) and 没 (méi) can be placed in front of a verb or adjective to negate its meaning. However, 不 and 没 are not usually interchangeable, so it's important to learn when you must use 不 as opposed to 没, and vice versa.

不 is for negating in the present and future

不 is generally used to negate an action that you do not want to do or do not intend to do (in the future). So expressing things like "I don't want to go" or "I'm not going" would be uses of 不.

Structure

Subject + 不 + Verb

Examples

Whether it's "don't wanna do it" or "not gonna do it," use 不:

• 我 今天 晚上 不 吃 饭。I am not eating tonight.
• 我 今天 晚上 不 想 吃 饭。Tonight I don't want to eat.
• 他 不 去 公园。He's not going to the park.
• 他 不 要 去 公园。He doesn't want to go to the park.
• 老板 今天 不 来 公司。The boss won't come to work today.
• 我 现在 不 知道。I don't know right now.
• 我 知道 明天 不 下雨。I know it's not going to rain tomorrow.
• 我 不 想 跟 他 一起 去。I don't want to go with him.
• 下 个 星期 我们 不 去 北京，我们 去 上海。Next week we won't go to Beijing, we will go to Shanghai.
• 很 多 孩子 不 要 很 便宜 的 东西。Many children don't want very cheap things.

不 is used to negate habitual actions

不 can be used to negate habitual actions, to express what you just aren't in the habit of doing, such as eating meat, or watching TV, or drinking alcohol. This is simply done by placing 不 in front of the verb.

Structure

Subject + 不 + Verb + Object

Examples

• 我 不 吃 肉。I don't eat meat.
• 我 不 看 电视。I don't watch TV.
• 我 不 喝 酒。I don't drink alcohol.
• 我 奶奶 不 用 手机。My grandma doesn't use a cellphone.
• 我 不 看 韩国 电影。I don't watch Korean movies.
• 他 不 喜欢 说话。He doesn't like to speak.
• 在 中国，我们 不 说 英文。In China, we don't speak english.
• 这 个 国家 的 人 不 洗手 吗？Don't the people in this country wash their hands?
• 我 爸爸 从 来 不 笑。My dad never laugh.

Please note that, while it is grammatically correct to use 没 in all the sentences above, 没 does not negate any habitual actions. The sentences above, if they contained 没 instead of 不, would express that the speaker didn't do the named activity (at one particular point in the past). So it would not be about habitual actions.

不 is normally used with adjectives

When it comes to a simple negation of an adjective (e.g. "not Adj"), use 不.

Structure

不 + Adj

Examples

• 面包 不 好吃。Bread is not good to eat.
• 超市 不 远。The supermarket is not far away.
• 今天 不 冷。Today it isn't cold.
• 我 不 高兴。I am not happy.
• 她 不 漂亮。She is not pretty.
• 你的 女朋友 不 难看。Your girlfriend is not ugly.
• 我们 不 饿。We're not hungry.
• 你 不 聪明。You are not clever.
• 我 觉得 Starbucks 的 咖啡 不 贵。I think the coffee at Starbucks isn't expensive.
• 你们 的 果汁 不 新鲜 了。Your fruit juice isn't fresh.

不 is used to ask questions

There are couple ways to use 不 to ask questions. One such way is through affirmative-negative questions. This is done by stating a verb and then immediately repeating that verb in a negative state (with 不):

Structure

Subject + Verb + 不 + Verb + Object

Examples

• 你 是 不 是 我的 老师？Are you my teacher or not？
• 今天 你 来 不 来？Are you coming today? (Literally: Today you come-not come?)
• 你 喜 不 喜欢 吃 中国菜?Do you like to Chinese food? (Literally: Do you like-not like Chinese food?)
• 你 在 这里，想 不 想 妈妈？You are here, do you miss your mom or not?
• 我们 去 不 去 北京？Are we going to Beijing or not?
• 你 喝 不 喝 茶？Do you drink tea or not?
• 你 爱 不 爱 我？Do you love me or not?
• 吃 不 吃 冰淇淋？Do you eat ice cream or not?
• 你 今天 上 不 上 课？Did you go to class today or not?
• 你 买 不 买？Are you buying or not?

不 can also be used to form tag questions. Tag questions use the positive-negative question form, but are placed at the end of the sentence. Tag questions are used to seek approval or acceptance for a statement, very similar to the English "OK?" or "right?" You can't use 没 for this.

• 我们 去 吃饭，好 不 好 ？ Let's go eat, is that OK?
• 你 是 我的 同学，对 不 对 ？ You are my classmate, right?
• 我们 喝 水，好 没 好。Let's drink water, OK does not have OK?
• 你 得 上 课，对 没 对。You should go to class, right not have right?

没 is used to negate past actions

没 and 没有 can both be used to negate actions that occurred in the past, or to say that something has not happened yet.

Structure

Subject + 没(有) + Verb + Object

Examples

• 他 没有 打 电话 给 我。He did not give me a call.
• 他 没有 上课。He did not go to class.
• 我 昨天 没 喝 葡萄酒。I did not drink wine yesterday.
• 我 昨天 不 喝 葡萄酒 。I not drink wine yesterday.

There are a few things worth noting in these examples. For one, it is still grammatically correct to leave out the 有 in the sentences using 没有. Also, the sentence using 不 would be grammatically correct, if not for the 昨天 ("yesterday") telling us that it is definitely the past we're talking about. That incorrect sentence using 不 would translate into *"I don't drink wine yesterday" as opposed to "I didn't drink wine yesterday."

Only 没 is used to negate 有

没 can be used to negate the verb 有 ("to have") to mean "do not have." You can only use 没 to convey this meaning. It is grammatically incorrect to use 不 to negate 有.

Structure

Subject + 没有 + Object

Examples

• 我 没有 钱。I don't have money.
• 我 不 有 钱。I not have money.
• 他 没有 女朋友。He doesn't have a girlfriend.
• 他 不 有 女朋友。He not have girlfriend.

There are times when you can leave out 有 entirely while still expressing 没有 (meaning "to not have" or "there is no"). One well-known example of this is 没办法 ("there is no way" [that's gonna happen]). Both 没 and 没有 are correct, however.

• 我 没 办法。I don't have a way.
• 我 没有 办法。I don't have a way.

(You can also use 没办法 to express other meanings.)

没 is used to make comparisons

没 or 没有 can be used to make simple comparisons meaning "not as... as":

Structure

Noun 1 + 没有 + Noun 2 + Adjective

Examples

• 我 的 钱 没有 他 的 钱 多。(Literally: "My money does not have his money many.")My money isn't as much as his.
• 你 的 钱 不 有 他 的 钱 多。 My money not have much as his.
• 你 没有 我 高兴。You are not as happy as me. (Literally: you do not have my happiness.)
• 你 不 有 我 高兴。You not have my happy.

You can only use 没 or 没有 for this purpose, and not 不.

不 is used almost exclusively with some verbs

Certain verbs just don't get negated by 没 or 没有 ever. These include the verbs 是 ("to be") and 在 ("to be (in a place)"), as well as some psychological verbs such as 知道 ("to know") and 认识 ("to know (a person)"). For these verbs, it's best to just take them on a case-by-case basis. Being aware of their existence can save you a fair bit of confusion.

• 他 以前 不 是 我的 朋友 。 He was not my friend before.
• 他 以前 没 是 我的 朋友 。 He did not have my friend before.
• 昨天 我 不 在 家 。 I was not home yesterday.
• 昨天 我 没 在 家 。 I did not have home yesterday.
• 昨天 我 不 知道 。 I didn't know yesterday.
• 昨天 我 没 知道 。 I did not have know yesterday.
• 他 以前 不 认识 她 。 He did not know her before.
• 他 以前 没 认识 她 。 He not have know her before.

Note that in non-standard Mandarin you might encounter exceptions to this rule. It's still useful to know the rule!

Sources and further reading

Websites

• http://www.docin.com/p-20925643.html
• http://wenku.baidu.com/view/e2e8eb2ce2bd960590c67703.html

Videos

• Yoyo Chinese: Negation word 不
• Yoyo Chinese: Negation word 没

Books

• Chinese: An Essential Grammar, Second Edition (pp. 141-4) →buy
• Integrated Chinese: Level 1, Part 1 (3rd ed) (pp. 137-9) →buy
• New Practical Chinese Reader 1 (新实用汉语课本1) (pp. 87) →buy
• New Practical Chinese Reader 1 (新实用汉语课本1)(2nd ed) (pp. 102, 250-1) →buy
• Chinese: An Essential Grammar, Second Edition (pp. 54-5) →buy
• New Practical Chinese Reader 3 (新实用汉语课本3) (pp. 33-4) →buy
• Chinese: An Essential Grammar, Second Edition (pp. 51) →buy
• 现代汉语八百词（增订本） (pp. 382) →buy
• Practicing HSK Grammar (语法精讲精炼) (pp. 32) →buy
• 现代汉语八百词（增订本） (pp. 383) →buy
• Integrated Chinese: Level 1, Part 1 (3rd ed) (pp. 31) →buy
• Integrated Chinese: Level 1, Part 2 (1st ed) (pp. 85-86)　→buy
• New Practical Chinese Reader 1 (新实用汉语课本1)(2nd ed) (pp. 218) →buy
• Reference:Chinese Grammar - Broken down into 100 items - Basic and Intermediate Levels (汉语语法百项讲练 - 初中级)(不 没p.156)→buy
• 40 Lessons for Basic Chinese Course (基础汉语40课上册） (p. 157-8)→buy