Se utilizan para conectar oraciones (relative clauses). Los pronombres relativos son los siguientes:
The girl that I met yesterday was really pretty.
Here's the school that I study in.
That boy, who is new in school, is cool.
That painting, which is really famous, was painted by Picasso.
The girl ,whose bike I borrowed, is my neighbour.
I went to London, where I used to live.