http://cybraryman.com/partsofspeech.html
http://www.myenglishimages.com/Vocabulary/Entries/2009/8/16_Advanced_Verbs.html
http://www.ego4u.com/en/business-english/grammar/conditional-sentences
http://hyperhomeschool.squarespace.com/building-language/2010/10/21/preposition-pizzazz.html
http://www.oup.com/elt/global/products/englishfile/elementary/