Fixed-case prepositions
Accusative prepositions include durch, für, gegen, ohne, um. Dative prepositions include aus, bei, mit, nach, seit, von, zu. The preposition determines the case here.
Understand the idea
A preposition can govern the case of its noun phrase. Fixed-case prepositions keep that case even when the sentence's action or word order changes. This is different from the separate two-way preposition system.
Build it step by step
Common accusative prepositions include durch, für, gegen, ohne and um. Common dative prepositions include aus, bei, mit, nach, seit, von and zu. After choosing the preposition, select an article or pronoun in its required case. Some common combinations contract, such as zu dem → zum and bei dem → beim.
See it in a sentence
Das Geschenk ist für den Mann.
Ich fahre mit dem Bus.
A useful memory aid
Learn prepositions inside useful phrases: für einen Freund, mit einer Freundin, ohne dich. Recall the whole phrase before analysing the ending.
A common trap
Do not choose the case from English alone. German and English prepositions rarely match in every situation, and a German preposition can have several meanings.