Relative pronouns

WHO - WHICH - THAT - WHOSE

	People	Things	Animals
WHO	X
WHICH		X	X
THAT	X	X	X
WHOSE (possessive)	X	X	X

Here you find exercises to practice these relative pronouns.
http://www.ego4u.com/en/cram-up/grammar/relative-clauses/exercises?02
http://www.englisch-hilfen.de/en/exercises/pronouns/relative_pronouns.htm
http://www.englishexercises.org/makeagame/viewgame.asp?id=3221