How do you form a relative clause in German?

Relative clauses are used to add extra information about a person, thing or event to a sentence, such as the bold part of this English sentence: The man who loves fast cars always drives on the motorway . The easiest way to build a sentence with a relative clause is to first write two sentences, one containing the main piece of information (The man always drives on the motorway - Der Mann fährt immer auf der Autobahn) and one containing the additional information (He likes fast cars - Er liebt schnelle Autos). Once you have those sentences you need to select a relative pronoun - that's the 'who', 'which' or 'what' of your phrase. In German, the most common relative pronouns are der, die, das, dem, den, denen. To select the relative pronoun you need to find out the gender and case of the person or thing you are describing in the relative clause. In this case, we know that 'der Mann' is masculine and it is in the nominative case because 'He' (the man) is the subject of the sentence containing the additional information. So we select 'der' - the masculine nominative pronoun - from our list. To build the clause we now replace the thing/person from our second sentence with the relative pronoun (Der liebt schnelle Autos) and move the verb to the end of the clause (Der schnelle Autos liebt). Finally, insert the additional information into the first sentence, remembering to introduce it with a comma: Der Mann, der schnelle Autos liebt, fährt immer auf der Autobahn.