Many foreign students are often confused about some similar words in Chinese. For example:不 and 没，which look the same, even though they are used quite differently.
“Bù” 不 and “méi”没 are both negative words. Here, I have listed several situations indicating how to use them properly. But remember, there are always overlaps and exceptions.
1. For expressing don’t have and there isn’t or there aren’t, you must use “méi you” or “méi”. you can not use “bù”. “Méi” can be used in the short term for “méi you”, usually you can replace each other.
- wŏ méi you shí jiān.(I have no time.)我没有时间。
- Wŏ méi you qián.(I have no money.)我没有钱。
- Wŏ méi kòng.(I have no time.)我没空。
- Yīng guó méi you dà xióng māo (panda). (There isn’t any panda in Britain.)英国没有大熊猫。
2.”Bù” is usually used to describe the change of the state, but “méi ”is usually to describe a negative fact.
- Chē bù zŏu le.车不走了. The Car doesn’t work. (The car was going before, but now it is not going any longer.)
- Chē méi zŏu.车没走。Car didn’t go.（The car is there, it hasn’t gone yet.)
- Tiān bù xià yŭ le.天不下雨了。It doesn’t rain.（It was raining before, but now it is not raining any longer.）
- Tiān méi xià yŭ.天没下雨。It didn’t rain.（It hasn’t rained. It didn’t rain.）
3.when you describe something that hasn’t taken place, you can use”méi you”. For example:
- Tā méi you lái. (He didn’t come.)他没有来。
- Wŏ méi you chī fàn.(I didn’t eat.)我没有吃饭。
- Wŏ méi you shōu dào (receive) tā de diàn zĭ yóu jiàn(Email).(I didn’t receive his email.)我没有收到他的电子邮件。
4. When you describe something has taken place and the change of state, which is a negative one, such as, disappeared, you use “méi ”. For example:
pí jiŭ méi you le.啤酒没有了。(There is not any beer.)（in this context,we usually use “le ”in the end of the sentence.）
5. When it is a personal decision and willingness, you use “bù”. For example:
- Tā bù lái le.他不来了。(He doesn’t come.)(It means he has decided not to come.)
- Tā méi lái .他没来。(He didn’t come.)（It just describes the fact that he didn’t come.）
- Wŏ bù chī fàn. 我不吃饭。(I don’t eat.)(It means I don’t want to eat.)
- wŏ bù xĭ huān pí jiŭ.我不喜欢啤酒。(I don’t like beer.)
6.When you give or have a negative judgement, attribute or manner of a certain thing or a fact, you use “bù”. For example:
- Wo jué de pí jiŭ bù hăo.我觉得啤酒不好。(I don’t think this beer is good.)
- Tā xiĕ (write) de zì (word, characters) bù hăo. 他写的字不好。(His writing is not good.)
About “bù”and “méi”, today we just started talking about it. However, I hope this helps you to use them in daily life instantly.