Prepositions express relations. They usually appear before the noun or pronoun to which they refer. Together with their nouns, they describe when, why, how or where something happens. A preposition always determines one of the 4 German cases for their noun.
Local Prepositions
Rule 1: Prepositions of place and direction correspond to the questions Where? Where to? Where from?
Typically, they are used with the dative or accusative case.
Rule 2: As an answer to the question Wo? (where), these local prepositions always precede the person or place:
For example:
Bei or An?
Rule 3: These two prepositions are often mistaken by beginners. Here's how to differentiate them:
- bei is used in connection with a person, a profession (like a doctor or a lawyer), or a place of work.
- an is used as an answer to the question of where someone/something is located and means “on”, “next to”.
Contraction of a Preposition and an Article
Rule 4: Some prepositions can be combined with an article to create one single word:
- in + dem = im (in the)
- in + das = ins (in the)
- zu + dem = zum (to the)
- zu + der = zur (to the)
- bei + dem = beim (at the)
- von + dem = vom (from the)
- an + dem = am (at the)
Please note that this list is not complete.