"That is why I am mad at him."
Translation:Deshalb bin ich sauer auf ihn.
Does anyone know of a good resource to know which words count as a position in the sentence? I know the rule of keeping the verb in the second position, but every now and then I'll come across a word that exists outside the sentence where you'd normally think it takes the first position...
I really like the Dartmouth German grammer site. Here's the word order section: http://www.dartmouth.edu/~deutsch/Grammatik/WordOrder/WordOrder.html
olimo is right. ""Das ist weil" would mean something like "That is because" if you translate it back to English. "darum" and "deshalb" are both correct. You'll also need to take care of the prepositions here, you cannot say "an ihnen". In German, you use "wütend" with the preposition "auf", so it would be "wütend auf ihn". You can trust me, even if I only have 8 levels of German here in duolingo - I am a German native speaker, I'm originally only here to learn Spanish ;) But I know the pain of trying to figure out which prepositions to use, we Germans have the same problem with the English ones. :)
The rule is "the verb should always come second". So if there's an adverb at the start, or a clause before the sentence, you swap them round.
That's a generalisation, but it should get you started. Conjunctions don't count, for instance. So it would still be, "Aber ich bin sauer auf ihn."
Er is Nominative, Ihn is Accusative, Ihm is Dative.
Duo explains about Accusative and Dative pronouns if you need help.
If it means "on", "auf" takes dative. If it means "onto", "auf" takes accusative.
I'm not sure if that's always true, but just remember that with dual prepositions, accusative means there's motion and dative means there's position.
Das ist auf dem Tisch = That is on the table
Stelle das auf den Tisch = Set that on/onto the table.