Negation (not, don't)

Negation says that something is not true, does not happen, or does not exist. English builds it with not, with don't / doesn't, or with negative to be.

To be

• I am not tired. / I'm not tired.
• She is not at home. / She isn't at home.
• We are not ready. / We aren't ready.

Other verbs in Present Simple — do / does

Do not put not straight onto go, like, work. Use an auxiliary:

• I / you / we / they: don't + infinitive: I don't drink coffee.
• he / she / it: doesn't + infinitive without -s: He doesn't like tea. (not doesn't likes)

• They don't work on Sundays.
• The Earth doesn't have two moons.

Can't

can + not → can't / cannot: I can't swim.

Short answers: Do you like tea? — No, I don't. · Is she here? — No, she isn't.