Simplified, the meaning of the German ‘in’ preposition changes according to the case.
In the dative case, which asks the question where? or in German, wo? and pertains to a space. The English equivalent would be: at or also in. Depending on the article of the object the possibilities are (1) for masculine and neutral articles: in dem or the short form, im (2) for feminine: in der.
In the accusative case, which asks the question where to? or wohin? and
refers to a change or movement of the object. The English equivalent
would be: into or simply in. Depending on the article of the object the possibilities are (1) for masculine article: in den (2) for feminine: in die (3) for neutral: in das or short form ins.
Of course, the German preposition ‘in’ can also be
associated with non-concrete or abstract ideas, such as a bracket of
time or a goal. The English and German equivalent would be within or innerhalb, respectively.
Here are a few common examples:
Tausende von Menschen stroemten ins Eisstadion. -[akk. movement of people]
Der Ball flog mitten in die Zuschauer. – [akk. movement of ball]
Wir waren in allen Punkten einer Meinung.
Treffen wir uns in einer halben Stunde vor dem Kino! – [dat. at a point in time]
Von Kindheit an mussten sie im elterlichen Geschaeft mithelfen. – [dat. in a trade]
Wer wohnt in dem Neubau an der Ecke? [dat.]
Herr Baur ist schon seit langem in Pension.
Lassen Sie den Prospekt ins Franzoesische uebersetzen? [akk. - a change from one language to another]
Tags: accusative case, article, dative case
