Two-Way Prepositions (Wechselpräpositionen)

I. Theory

In German, each preposition governs a case. However, there are certain commonly used prepositions that can govern either the accusative or the dative depending on their function in the sentence. For the most part, this is when these prepositions are conveying movement or a lack of movement. In English, since we don’t use cases to show this nuance, we have modified prepositions:

Ich gehe ins (in das) Haus (accusative). I go into the house. but Ich bin im (in dem) Haus (dative). I am in the house. *Wir fahren hinter die Berge. (accusative) We drive behind the mountains. but *Die Stadt liegt hinter den Bergen (dative). The city lies behind the mountains.

* In these examples, we see no distinction in English. However, in the example below, we see that the German tells us more than the English:

Der Hubschrauber fliegt über den Wald. The helicopter flies over the forest (it is flying from one location to another). Der Hubschrauber fliegt über dem Wald. The helicopter flies over the forest (it is stationary in the air).

II. 2-Way Prepositions

The following prepositions can take either dative or accusative case: an, auf, hinter, in, neben, über, entlang, unter, vor and zwischen. All others govern either dative or accusative.

Ich ging an die Bar, um einen Drink zu holen. I went (up) to the bar to get a drink (accusative). Die Männer stehen an der Bar. The men stand at the bar. (dative) Das Fahrrad steht zwischen den Autos. The bike stands between the cars. (dative) Der Fahrradfahrer fährt zwischen die Autos. The cyclist rides between the cars. (accusative)

III. Contractions

As seen in some of the examples above, certain German prepositions contract with the definite article. These contractions are preferred over saying/writing both the preposition and the article separately. Though there are others, the following contractions pertain to two-way prepositions only.

In + das = ins Die Lehrerin kommt ins Zimmer. The teacher comes into the room. In + dem= im Während des Sturms bleiben wir im Hotel. We are staying in the hotel during the storm. An + das = ans In den Ferien fahren wir ans Meer. On break, we will drive to the beach. An + dem= am Am Freitag fliegt meine Schwester nach Afrika. On Friday, my sister is flying to Africa. Auf + das= aufs Ein Hochschulabschluss ist oft aufs engste mit anderen Qualifikationen verbunden. A university diploma is often closely linked to other qualifications.