できない

The English modal auxiliary verbs are a subset of the English auxiliary verbs used mostly to express modality, properties such as possibility and obligation. They can most easily be distinguished from other verbs by their defectiveness (they do not have participles or plain forms) and by their lack of the ending ‑(e)s for the third-person singular.The central English modal auxiliary verbs are can (with could), may (with might), shall (with should), will (with would), and must. A few other verbs are usually also classed as modals: ought, and (in certain uses) dare, and need. Use (/jus/, rhyming with "goose") is included as well. Other expressions, notably had better, share some of their characteristics.