Modal Auxiliary Verbs

You may also know these verbs as “helping verbs” because that’s exactly what they do, help to convey the idea expressed by another verb.

There are six modal auxiliaries in German, here presented with their definitions and a rough English equivalent:

dürfen	permission	to be allowed to, may
wollen	intention, desire	to want to
sollen	duty, expectancy	to have to, shall
müssen	necessity, compulsion	to have to, must
mögen	possibility	to possibly do, might
können	ability	to be able to, can

These auxiliaries are almost always followed by infinitives. The infinitives never take zu.

Wir müssen es lernen.
We have to learn it.

Ich kann dieses Buch nicht verstehen.
I can’t understand this book.