A1
Saying no with 不
How 不 negates verbs and adjectives in Chinese, why it changes tone before a fourth-tone syllable, and the one verb that refuses it entirely.
不 goes directly in front of whatever it negates. No auxiliary, no do, no change to the verb.
我不喝咖啡。
Wǒ bù hē kāfēi.
I don’t drink coffee.
今天不冷。
Jīntiān bù lěng.
It isn’t cold today.
我明天不去。
Wǒ míngtiān bú qù.
I’m not going tomorrow.
What 不 covers
Habits, preferences, states, intentions and anything in the future — which is to say almost everything except a completed action.
他不喜歡辣的。
Tā bù xǐhuan là de.
He doesn’t like spicy food.
我不會開車。
Wǒ bú huì kāichē.
I can’t drive.
For something that did not happen — a past event rather than a standing fact — Chinese uses 沒 instead. 我不去 is I’m not going; 我沒去 is I didn’t go. That is a different word with a different job, and it has its own page.
不 changes tone before a fourth tone
不 is a fourth-tone syllable, and two fourth tones in a row do not sit comfortably, so before another fourth tone it rises to a second: bú.
不是
bú shì
is not
不去
bú qù
not going
不要
bú yào
don’t want
Before first, second or third tones it stays bù — 不冷 bù lěng, 不喝 bù hē. The character never changes; only the sound does. Pinyin in textbooks is inconsistent about writing this, so both spellings are common in print and the pronunciation is the same either way.
有 refuses 不
有 is the exception, and it is absolute: 有 is negated by 沒 whatever the tense, whatever the sentence.
我不有時間。
我沒有時間。
There is no context in which 不有 is correct. 沒有 covers don’t have and didn’t have alike, and shortens to 沒 in speech: 我沒時間。
Where 不 sits when there is more than one verb
In front of the first one — the auxiliary, not the main verb. Negating the wrong one is a real mistake with a real change of meaning.
我不想去。
Wǒ bù xiǎng qù.
I don’t want to go.
我想不去。
我不想去。
我想不去 is not ungrammatical, which is what makes it dangerous — it says what I want is to not go, a deliberate decision rather than an absence of enthusiasm.