Modal Words: можно, нужно, надо, нельзя

Russian uses special impersonal modal words that express necessity, permission, or prohibition. The person who "needs" or "can" is in the Dative case.

The four most important modal words

Examples

• Мне можно войти? (May I come in?)
• Здесь нельзя курить (Smoking is not allowed here / one cannot smoke here).
• Тебе надо отдохнуть (You need to rest).
• Ему нужно работать (He needs to work).

Note

• Можно and нельзя are about permission/possibility.
• Надо and нужно are about necessity (similar to must/have to).
• All four are followed by the infinitive.