These questions ask you to recognise whether someone is requesting permission or granting it, then build the modal phrase correctly. Decide what the speaker is doing before you decide how formal the sentence should sound.
Identify the speech act first
Begin with the direction of the permission. A question spoken by the person who wants to act is a request; a reply or statement from the person with authority is a grant. Can and may work in both directions. May is especially suitable when the setting or wording is formal. Could is useful for a polite request, but a person giving permission normally uses can or may because those forms perform the grant directly.
| Communicative signal | Pattern to use |
|---|---|
| An ordinary request for permission | Use Can plus subject plus bare verb. |
| A formal request for permission | Use May plus subject plus bare verb. |
| A more tentative or polite request | Use Could plus subject plus bare verb. |
| A direct grant of permission | Use subject plus can or may plus bare verb; may gives the grant a more formal tone. |
| A merely possible or hypothetical action | Could and might sometimes describe possibility, but that meaning does not itself authorise the action. |
Once the meaning is settled, check the shape. In a statement, the subject comes before the modal. In a permission question, the modal moves before the subject. The main verb follows immediately in its bare form: there is no to and no -ing ending between the modal and that verb. The modal itself never gains -s for a third-person subject.
The traps
| Tempting form | How to reject it |
|---|---|
| Using could or might when an authority is granting permission now | Those forms can leave the action hypothetical. For an actual grant, choose can or may and let the level of formality decide between them. |
| Adding to after can, may or could | Core modals take the bare verb directly. Remove to instead of changing the time or politeness of the sentence. |
| Following the modal with an -ing form | An -ing form cannot fill the bare-verb position after these modals. Keep the modal and return the action verb to its base form. |
| Adding -s to may or can | The modal stays unchanged with every subject. Person and number do not create forms such as mays or cans. |
| Leaving the subject out of a permission question | A full request needs modal plus subject plus bare verb. Moving the modal to the front does not remove the subject. |
Try it
Repair only the modal phrase in the manager's grant, replacing the error in 'may to rehearse': You ___ in Studio Two after six.
Select all that apply: which questions correctly ask permission to leave a bicycle in the courtyard?
- Can I leave my bicycle in the courtyard?
- May I leave my bicycle in the courtyard?
- Must I leave my bicycle in the courtyard?
- May I to leave my bicycle in the courtyard?
Which reply contains the grant error in the could-versus-can-or-may permission contrast?
- The coach replied, 'You can use the indoor track until noon.'
- The ranger said, 'You may camp beside the marked spring tonight.'
- The porter answered, 'You can leave the instrument behind the desk.'
- The curator replied, 'You could view the manuscript room this afternoon.'