Apart from specifying elements of the main phrase, a
relative clause can also specify an idea of a main clause
or be it a group of words.
Let's have a look at an example
Sie haben das
Projekt beendet, was
sich als eine schlechte Idee erwies.
= They have terminated the project which
turned out to be a bad idea.
The relative pronoun which
(was) does not refer
to a noun, but to the meaning of the main phrase they
have terminated the project. The German relative
pronoun in these cases is was.
Sie haben
das Projekt aufgegeben, wassich als schlechte
Idee erwies.
