Helping Verbs
Helping verbs (also called auxiliary verbs) work alongside a main verb to build tenses, form questions, make negatives, and express meanings like ability, obligation, and possibility.
What is a helping verb?
A helping verb (or auxiliary verb) is a verb that supports the main verb in a sentence. It does not carry the core meaning — the main verb does that — but it adds information about tense, voice, mood, or modality.
She is working. (is = helping verb; working = main verb)
They have finished. (have = helping; finished = main)
He will call you. (will = helping; call = main)
Do you understand? (do = helping; understand = main)
Primary auxiliary verbs: be, have, do
The three primary auxiliaries are used to build tenses, form questions, make negatives, and create the passive voice.
| Auxiliary | Use | Examples |
|---|---|---|
| be (am/is/are/was/were) | Continuous tenses; passive voice | She is reading. The letter was written. |
| have (has/had) | Perfect tenses | I have eaten. She had left already. |
| do (does/did) | Questions; negatives; emphasis | Do you know? She doesn't come. I DO care! |
Modal auxiliary verbs
Modal auxiliaries express ideas like ability, permission, obligation, possibility, and advice. They always come before the base form of the main verb (no -s, -ing, or -ed).
| Modal | Main use | Example |
|---|---|---|
| can | Ability; informal permission | She can swim. Can I open the window? |
| could | Past ability; polite request; possibility | He could run fast. Could you help me? |
| will | Future; predictions; offers | It will rain tomorrow. I'll help you. |
| would | Conditional; polite requests | I would come if I could. Would you like tea? |
| shall | Offers; suggestions (mainly BrE) | Shall we go? Shall I carry that? |
| should | Advice; expectation | You should see a doctor. He should be here soon. |
| may | Formal permission; possibility | You may leave. It may rain later. |
| might | Possibility (less certain than may) | She might come. I might be wrong. |
| must | Strong obligation; logical deduction | You must stop. He must be tired. |
Key properties of modal verbs
- Always followed by the base form (infinitive without to): She can swim (not: she can swims / can to swim)
- No -s in the third person: He should go (not: he shoulds go)
- Form negatives by adding not: cannot / can't, should not / shouldn't
- Form questions by inverting with the subject: Can she swim? Should he go?
- They have no infinitive, gerund, or participle form
Can she drive? → She cannot drive. / She can't drive.
Should we leave? → We should not leave. / We shouldn't leave.
Will it rain? → It will not rain. / It won't rain.
Tip: The word do as an auxiliary has a special emphatic use in positive statements: I do love this city! She does understand! This adds strong emphasis or contradiction — useful when someone has doubted you.