The most common relative pronoun is “que”. It can be used to refer to both persons and things, in either the subject or the object position. “Que” is the Spanish equivalent of the English words who, whom, which, and that. The relative pronoun “quien” is used only to refer to people, and has a plural form “quienes”. (There is no masculine/feminine distinction.) For example, if i wanted to say, “Juan has two dogs that are black”, “juan tiene dos perros que son negros”. My uncle, who is a professor, is coming to visit me today. “Mi tío, quien es profesor, viene a visitarme hoy día.” Relative pronouns are not an easy concept, but today i truly made progress on furthering my knowledge on relative pronouns.