A relative clause adds information about a noun: “the man who lives next door.” In German the linking word (the relative pronoun) looks like the definite article — and, being a subordinate clause, it sends its verb to the end.
Two questions pick the pronoun
- Gender & number come from the noun it refers back to (der Mann → der/den/dem …).
- Case comes from the pronoun's job inside the relative clause, not from the main sentence.
| Case | Masc. | Fem. | Neut. | Plural |
|---|---|---|---|---|
| Nominative | der | die | das | die |
| Accusative | den | die | das | die |
| Dative | dem | der | dem | denen |
Der Mann, der dort wohnt, ist Arzt.
The man who lives there is a doctor.
subject in the clause → der (nom.)
Das Buch, das ich lese, ist spannend.
The book that I'm reading is exciting.
object in the clause → das (acc.)
Die Frau, der ich helfe, ist meine Nachbarin.
The woman I'm helping is my neighbour.
helfen takes dative → der (dat.)
✗Der Mann, der ich gestern getroffen habe, …
✓Der Mann, den ich gestern getroffen habe, …
He's the object of treffen inside the clause → accusative den.
✗Das Auto, das ist rot, gehört mir.
✓Das Auto, das rot ist, gehört mir.
The clause verb ist goes to the end.
Tipp · Always put a comma before the relative pronoun — German relative clauses are fenced off with commas.