I. Theory
Adjectives in German are often paired with prepositions. To review: a preposition is a word placed before or after a noun to show its relationship to other parts of the sentence. Prepositions are commonly found with adjectives in English as well: (trilled
with, afraid
of, concerned
about, etc.)
II. Cases
In German, prepositions take cases and thus when using them with adjectives, it is necessary to know if the particular preposition takes the accusative, dative, or genitive. For two-way prepositions (discussed at length in another lesson), the adjective itself determines if the preposition takes accusative or dative.