Relative pronouns - practice

http://www.englisch-hilfen.de/en/exercises/pronouns/relative_pronouns.htm
http://www.ego4u.com/en/cram-up/grammar/relative-clauses/exercises?02
http://www.ego4u.com/en/cram-up/grammar/relative-clauses/exercises?10
http://www.ego4u.com/en/cram-up/grammar/relative-clauses/exercises?06
http://www.ego4u.com/en/read-on/countries/uk/tour/stonehenge#exercises
http://www.ego4u.com/en/cram-up/grammar/relative-clauses/exercises?07
http://www.ego4u.com/en/read-on/countries/usa/tour/san-francisco#exercises
http://www.ego4u.com/en/cram-up/tests/relative-clauses-2