
deren is one of the B1 words in the free course — with this picture, the audio, and spaced repetition.
deren
whose (fem./pl.)
/ˈdeːʁən/Examples — deren in a sentence
Das ist die Frau, deren Hund uns gebissen hat.
That is the woman whose dog bit us.
Wir trafen die Studenten, deren Ergebnisse beeindruckend waren.
We met the students whose results were impressive.
How to remember it
DEH-ren sounds like 'Daring' — 'Whose' daring adventure is this? (Referring to a group of women or things).