Joining sentences with the relative pronouns: WHO, WHICH, WHERE, WHOSE

FORM & MEANING.
A relative clause tells us which thing or person the speaker means.
"The man who works in the bank is my brother" - 'who works in the bank' tells us which man.

• We use who in relative clauses for a person. Who is followed by a verb.
  
• We use whose in relative clauses instead of his/hers/theirs. Whose is followed by a noun.
  
• We use where in relative clauses to talk about a place. Where is followed by a noun or pronoun.
  
• We use which (and that) in relative clauses to talk about a thing.
  

USE.
Relative pronouns are words like who, which, where and whose. A relative pronoun serves two purposes. It acts as the subject or the object (who, which), the place (where) or possessive pronoun (whose) in the relative clause. It also serves as a conjunction connecting the two clauses.
Examples:
I have a friend. She lives in New England.
I have a friend who lives in New England.
PRACTICE.
http://www.ecenglish.com/learnenglish/lessons/relative-prnouns-who-whose-where-which
http://www.englishexercises.org/makeagame/viewgame.asp?id=3221
http://roble.pntic.mec.es/dgub0004/relativesworksheet.doc