Negation with 不
【一14】否定副词“不”
Tone colorsā tone 1á tone 2ǎ tone 3à tone 4a neutral
Subject + 不 + Verb / Adjective
不 (bù) negates the present, the future, habits and states: 我不喝茶 (I don't drink tea), 今天不冷 (it's not cold today), 他明天不去 (he isn't going tomorrow).
It goes right before the verb or adjective, and before modal verbs: 不会, 不想.
Tone change: before a 4th tone, 不 becomes bú: 不是 bú shì, 不去 bú qù, 不对 bú duì. Otherwise it stays bù: 不好 bù hǎo, 不忙 bù máng.
Two exceptions: 有 is negated with 没 (没有), and past actions use 没 (covered later).
Examples
今天不热。
Jīntiān bú rè.It isn't hot today.
他不去医院。
Tā bú qù yīyuàn.He's not going to the hospital.
我不喜欢看电视。
Wǒ bù xǐhuan kàn diànshì.I don't like watching TV.
他不吃包子。
Tā bù chī bāozi.He doesn't eat steamed buns.
Common mistakes
✗ 我不有 → ✓ 我没有.
✗ 我喝不茶 → ✓ 我不喝茶 (不 before the verb).
Tone: ✗ bù shì → ✓ bú shì.