can
ability or permission · She can drive.
Grammar bridge
Modals change the message
20 / 27
should
advice · You should review.
must
obligation or strong deduction · You must attend.
may / might
possibility · The plane may have been hit.
Form never changes: modal + base verb. No -s. No to.
Grammar reference: Class 3, slides 34–45 — modal form, meaning, and certainty.