La madre de Juan, la que/la cual tuvo un accidente, es mi vecina.
Juan's mother, who / who had an accident, is my neighbour.

Mi abuela, quien era la madre de mi madre, me quería mucho. 
My grandmother, who was my mother's mother, loved me very much.

Isabel, cuyas gafas son rojas, es una chica excelente.
Isabel, whose glasses are red, is an excellent girl.