‘Méi 没’ and ‘bù 不’ are both negation words in Mandarin Chinese, but we use them in different ways. To use them correctly is notoriously difficult for many Chinese language learners.
Using ‘bù 不’
First, to indicate that an action does not happen now or will not happen in the future, use the negation word ‘bù 不’. For example, “I don’t eat breakfast” (我不吃早饭 Wǒ bù chīzǎofàn). “I don’t want to eat breakfast tomorrow” (我明天不想吃早饭 Wǒ míngtiān bùxiǎng chīzǎofàn).
Second, to indicate that an action did not happen in the past. In this situation, you should use the negation word ‘méi 没’ or ‘méi yǒu 没有’. For example, “I didn’t eat breakfast” (我没吃早饭 Wǒ méi chīzǎofàn).
‘Méi 没’ and ‘bù 不’ don’t mean the same thing
You may think ‘bù 不’ and ‘méi 没’ mean the same thing but they don’t. Let’s compare these two sentences:
“我不吃早饭 Wǒ bù chīzǎofàn” means I don’t eat breakfast. When you use ‘bù 不’ to negate a verb, it means the action doesn’t happen or will not happen. This sentence implies that I don’t have the habit of eating breakfast. I just don’t do that.
But “我没吃早饭 Wǒ méi chīzǎofàn” means I didn’t eat breakfast yet. Maybe I forgot to eat breakfast or maybe I didn’t have time to eat breakfast, the result is that I didn’t have breakfast.
Affirmative Expressions with 不 (Bù) and 没 (Méi)
不 and 没 usually indicate negative expressions which makes it confusing since they can also represent affirmative expressions. Here are three ways 不 and 没 can be used in affirmative expressions:
Very easy versus not very easy (好容易 VS 好不容易)
容易（rónɡyì) means “easy”, and here 好 (hǎo) is used as an adverb like 很（hěn: very). In this sense, these two phrases are expressing two opposite meanings. 好容易 means very easy and 好不容易 means very not easy.
Here’s the trick. They are both used before verbs to indicate how difficult it is to do something.
1. I finally passed HSK test for level 6.
- 我好容易通过了HSK六级考试。(Wǒ hǎo rónɡyì tōnɡɡuòle liùjí kǎoshì.)
- 我好不容易通过了HSK六级考试。(Wǒ hǎo bù rónɡyì tōnɡɡuòle liùjí kǎoshì.)
2. We finally climbed to the mountain top.
- 我们好容易爬到了山顶。(Wǒmen hǎo rónɡyì pá dàole shāndǐnɡ.)
- 我们好不容易爬到了山顶。(Wǒmen hǎo bù rónɡyì pá dàole shāndǐnɡ.)
3. She finally persuaded me.
- 她好容易说服了我。(Tā hǎo rónɡyì shuōfúle wǒ.)
- 她好不容易说服了我。(Tā hǎo bù rónɡyì shuōfúle wǒ.)
Almost versus almost (差点 VS 差点没)
When they are followed by things that people want to happen, both 差点(chàdiǎn) and 差点没(chàdiǎn méi) express the opposite meanings for the following verbs.
1. I almost passed the HSK test for level 6. (Even though there’s no negative word in the following example, it still means “I didn’t pass the test”.)
- 我差点通过了HSK六级考试。(Wǒ chàdiǎn tōnɡɡuòle liùjí kǎoshì.)
2. I just barely passed the HSK test for level 6. (There’s a negative word 没in this example, but it means “I passed the test”.)
- 我差点没通过HSK六级考试. (Wǒ chàdiǎn méi tōnɡɡuò liùjí kǎoshì.)
When they are followed by things that people don’t want to happen, both 差点(chàdiǎn) and 差点没(chàdiǎn méi) mean that thing didn’t happen.
1. I almost broke the cup. (Both the following sentences mean “I didn’t break the cup”.)
- 我差点摔坏了杯子。(Wǒ chàdiǎn shuāihuàile bēizi.)
- 我差点没摔坏杯子。(Wǒ chàdiǎn méi shuāihuài bēizi.)
2. My wallet almost got stolen. (Both the following sentences mean “My wallet wasn’t stolen”.)
- 我的钱包差点被偷了。(Wǒde qiánbāo chàdiǎn bèi tōule.)
- 我的钱包差点没被偷。(Wǒde qiánbāo chàdiǎn méi bèi tōu.)
When we use 可不 or 可不是 as an independent expression, even with negative word 不, it means “Exactly!”.
- A：地铁上的人真多！(There are so many people on the subway.)
- B：可不（是）！我差点没挤上去。(That’s so true. I just barely squeezed on.)
- A: Dìtiě shànɡ rén zhēn duō!
- B: Kěbú(shì)！Wǒ chàdiǎn méi jǐ shànɡqù.