A yes/no question is a question that expects yes or no as the answer. In English, these questions are formed by moving an auxiliary verb before the subject — a process called inversion.
The type of auxiliary determines exactly how the question is built. There are three patterns to learn.
Questions with be
When be is the main verb, move it directly before the subject. No extra words are needed.
This works the same way in every tense where be appears as the main verb: am, is, are, was, were.
Questions with do, does, did
Most English verbs do not have a built-in auxiliary. For these verbs, English adds do, does, or did at the front, and the main verb returns to its base form — without -s, -ed, or any other ending.
The choice between do, does, and did depends on tense and subject.
| TENSE | SUBJECT | AUXILIARY |
|---|---|---|
| present | I / you / we / they | do |
| present | he / she / it | does |
| past | all subjects | did |
Notice that the third-person -s moves from the verb to the auxiliary: she works becomes does she work, not does she works. The same logic applies to past tense: they arrived becomes did they arrive, not did they arrived.
Questions with other auxiliaries
When the sentence already contains an auxiliary verb — can, will, have, should, must, might — move that auxiliary before the subject. The main verb stays in place.
If the sentence has more than one auxiliary, only the first one moves.
The inversion rule
All three patterns follow one general formula:
auxiliary + subject + main verb
The only thing that changes is which word serves as the auxiliary. With be alone, be moves. With ordinary verbs that have no auxiliary, do/does/did is added. With modals and other auxiliaries, the first auxiliary moves.
Negative yes/no questions
A yes/no question can be made negative by adding not (usually contracted to n't) to the auxiliary. These questions often express surprise, expectation, or a push toward agreement.
The contracted form (don't, doesn't, isn't, can't, won't) is standard in everyday speech and writing. The uncontracted form (do you not, is she not) sounds formal and is rare outside legal or academic contexts.
Common mistakes
Forgetting do/does/did
Keeping the -s or -ed ending after does/did
Using do/does with be
Using do/does with modals
Wrong auxiliary form