Breakdown of Der Mörder dachte an das Blut an der Wand.
an
at, on (vertical) / to (addressee) / of (in quantity/stock expressions)
die Wand
the wall
denken an
to think about
der Mörder
the murderer
Questions & Answers about Der Mörder dachte an das Blut an der Wand.
Why is dachte considered a "mixed verb"?
Dachte is the simple past (Präteritum) of denken (to think). It is called a mixed verb because it mixes two patterns: it changes its stem vowel from 'e' to 'a' like a strong (irregular) verb, but it also takes the -te ending like a weak (regular) verb. Notice that the consonants also change, from nk to ch!
Why does the sentence use an das Blut instead of a word like über for "about"?
In German, the standard phrase for "to think about [something/someone]" is denken an. When an is used as a fixed preposition with denken, it always takes the accusative case. Since Blut is a neuter noun, it becomes an das Blut.
The sentence says an das Blut (accusative) but an der Wand (dative). Why does the same preposition take two different cases here?
The first an is strictly tied to the verb denken, which requires the accusative case for the object you are thinking about. The second an is a two-way preposition answering the question "where?" (location). Because the blood is in a fixed position on the wall rather than moving onto it, it takes the dative case. Wand is a feminine noun, so it changes to der Wand.
Could I say Der Mörder hat an das Blut gedacht instead?