UNIT 3

Click here and you will find some interesting grammar exercises

http://www.oup.com/elt/global/products/englishfile/elementary/a_grammar/file01/
http://www.oup.com/elt/global/products/englishfile/elementary/a_grammar/file02/
http://www.oup.com/elt/global/products/englishfile/elementary/a_grammar/file03/
http://www.oup.com/elt/global/products/englishfile/elementary/a_grammar/file04/
http://www.isabelperez.com/grammar.htm#Grammar