Hier darf man nicht rauchen.

In this lesson you will learn the last of the modal verbs, dürfen. You already know the others. We use dürfen to express that a person has permission or the right to do something. This permission is usually given by someone in a position of authority, like a parent, doctor, or official.

Sie dürfen Wasser oder Tee trinken.

Hier dürfen Sie zwei Stunden parken.

Similarly, the authorities can deny someone permission to do something, in which case dürfen would be used with negation.

Sie dürfen keinen Kaffee trinken.

Hier dürfen Sie nicht parken.

Conjugation:

As with most of the other modal verbs, the vowel changes in the singular form; the verb form is the same in the first- and third-person singular.

Revision: müssen

As a comparison, take another look at sentences that use the modal verb müssen:

The verb müssen expresses a necessity or requirement; a person is forced to do something:

Er muss arbeiten. (He has to work because he needs money in order to live.)

When the verb müssen is negated, it means there is neither pressure to do something, nor is it expressly forbidden. It means that it is not necessary for a person to do something, but they can do it if they like.

Er muss nicht arbeiten. (He is rich and has enough money to live on, but perhaps he chooses to work because he enjoys it.)