Relative pronouns

RELATIVE PRONOUNS ("pronomi relativi") introduce a subordinate clause and represent persons or things mentioned previously. They can function as either subject or object pronouns without any change in form.
The most common relative pronouns are:
1) "che" or "il quale" <who, which, that>, referring to a specific antecedent:
"L'uomo che hai visto è italiano" <The man you saw is Italian>;
"Giulia, la quale è italiana, non parla inglese" <Julia, who is Italian, doesn't speak English>;
2) "quel che," "quello che" or "ci&ograve; che" <what>, referring to an unspecified antecedent:
"Quel che ha fatto non m'interessa" <What she did doesn't interest me>;
"Non so quello che ha fatto" <I don't know what she's done>;
"Fa ci&ograve; che vuole" <She does what she wants>;
3) the impersonal pronoun "chi" <the one who/whom>:
"Chi ride vince" <He who laughs wins>.

After a preposition, the invariable pronoun "cui" is used in place of "che":
"Ecco la signora di cui parlai" <Here is the woman of whom I spoke>.