useful websites to practise word formation

http://www.bbc.co.uk/apps/ifl/worldservice/quiznet/quizengine?ContentType=text/html;quiz=1433_word_formation

http://esl.about.com/library/quiz/blvocabquiz_wordform1.htm

http://www.uefap.com/vocab/exercise/build/form_v2.htm