Spanish Relative Pronouns - Pronombres Relativos (Médicos)
que - who, which, that
quien - who
Que is invariable, and either as subject or object of a verb refers to persons or things.
el hombre que vino - the man who came
los hombres que vimos - the men whom we saw
la casa en que vivo - the house in which I live
los libros de que hablo - the books of which I speak
Quien (plural quienes) agrees in number with its antecedent, and refers only to persons.
el hombre a quien ví - the man whom I saw
as niñas de quienes hablo - the girls of whom I speak
When que refers to persons it cannot follow a preposition.
la casa en que vivo - the house in which I live
la niña que ví - the child whom I saw
la niña a quien ví - the child whom I saw
Relative pronouns are never omitted in Spanish.
la sillas que compré - the chairs I bought
The preposition always precedes the relative pronoun.
el señor de quien le hablé - the gentleman I spoke to you about.
I desire a womanservant and a manservant, and a secretary in whom I can trust.
They told us a few interesting and humorous stories with which we were much amused.
He always gave presents to the children, with which they amused themselves much.
The neuter forms lo que, lo cual refer to a whole clause, idea, or phrase:
He gave me a book, a thing which pleased me.
Quien may often include its antecedent:
She was the one who gave her the box.
He who went yesterday did it.
the man whose courage is well known
I lived in a village, the name of which I have forgotten.
Cuanto (-a, -os, -as), when used as a relative, may include its antecedent and means ' as much as,' ' as many as,' ' all that':
He gave me all he had.
He spoke to as many persons as he could.