Relative Pronoun Cases
I'm having trouble determining which case to use when dealing with relative pronouns. Duolingo gives a nice chart of which word to use in each case and gender, but I cannot find instruction on when to use which case.
Examples: "Ich habe ein Auto, das rot ist." -> (Nominative or accusative?) Neuter
"Das ist der Mann, dem ich geholfen habe." -> Dative Masculine
I do not perceive any reason why the cases should be different. What's going on here?
And thank you all for your time.
Your first example I believe, used the nominative case.
Here is my basic explanation of the German cases. Someone please correct me if my notes are wrong.
Nominative - the entity / object preforming the action.
Accusative - the entity / object that is directly affected by the action.
Dative - the entity / object that is indirectly affected by the action.
Genitive - the entity / object of possession.
Der Wolf frisst den Apfel. I'm using den because the apple is directly being affected by the wolf eating it.
Der Wolf gibt dem Fuchs einen Apfel. Dem is used because the fox isn't having any action taken upon it but is still involved with the wolf's action. Den is used because the apple is directly being given to the fox by the wolf.
In short, the way I usually handle cases for anything that isn't preforming the action is, if there isn't any physical action being acted upon an object or entity but is still part of the action, I use the dative case. If the object or entity is being physically affected by the action, then I use the Accusative.
Correct, now specifically for relative clauses:
The relative pronoun has to agree with the noun it refers to in gender, but not in case. It always takes the case that matches the role it has in the relative clause:
Der Apfel, den ich esse, schmeckt süß.
The apple is the subject of the main clause (er schmeckt süß) -> nominative (der Apfel)
But it is the direct object of the relative clause (ich esse ihn) -> accusative (den)
In the second sentence, the man becomes an (indirect) "object" that you are doing something to, while in the first sentence, the car simply is - nobody else involved, no actions performed by one on the other.
Read this, it should help (look at all five pages, but they are very short):