Negatives and Questions: Using Do and Does

The single most common beginner mistake in English is leaving out do or does. Many languages build negatives and questions without a helper verb; English does not.

Negatives

Add don't (I / you / we / they) or doesn't (he / she / it) before the base verb.

• ❌ I no like coffee. ❌ I not like coffee.
• ✅ I don't like coffee.
• ✅ She doesn't like coffee.

The -s moves onto doesn't, so the main verb loses it: She doesn't like (not "doesn't likes").

Questions

Put Do or Does at the front.

• ❌ You like tea?
• ✅ Do you like tea?
• ✅ Does he work here?

Again: Does he work, not "Does he works".

Questions that start with a question word

What, where, when, why, how go before the helper — everything else stays the same.

• Where do you live?
• What does she do?
• Why don't they answer?

Word order, fixed — question word, then do/does, then subject, then base verb. Where — do — you — work?

The exception: asking about the subject

When who or what is the subject of the sentence, English drops the helper entirely.

• ✅ Who lives here? (not "Who does live here?")
• ✅ What happened? (not "What did happen?")

Compare: Who does she know? — here she is the subject, so does comes back.

Short answers

English rarely answers with just yes or no — it repeats the helper.

• Do you speak French? — Yes, I do. / No, I don't.
• Does she live here? — Yes, she does. / No, she doesn't.

The exception: be

The verb be (am / is / are) needs no helper at all.

• ✅ I am not tired. (not "I don't be tired")
• ✅ Are you ready? (not "Do you be ready?")

The same is true of modal verbs — can, will, should, must act as their own helper:

• ✅ I can't swim. / Can you swim?
• ✅ She won't come. / Will she come?

Full forms and contractions

Both are correct; the difference is register, not grammar.

Speaking & email to a colleague	Formal writing
I don't agree	I do not agree
She doesn't have it	She does not have it
Isn't it ready?	Is it not ready?

In speech, the contraction is the default — the full form sounds emphatic, as if you are insisting.

Quick summary

	Positive	Negative	Question
I / you / we / they	I work	I don't work	Do you work?
he / she / it	He works	He doesn't work	Does he work?
be	I am late	I am not late	Are you late?
modal	I can swim	I can't swim	Can you swim?

Three questions, three patterns

A: Where do you work?

B: At the school on Mill Road. Do you know it?

A: I don't think so. Who teaches there — anyone I'd know?

B: Probably not. It isn't a big place.

Do you know takes the helper; Who teaches drops it because who is the subject; isn't is the verb be, which never needed one.

Try it yourself

The quiz below focuses on exactly where the -s belongs and when be breaks the pattern.