Simple Present vs Present Continuous and more

http://www.oup.com/elt/global/products/englishfile/preint/a_grammar/file01/

Questions

http://ww2.college-em.qc.ca/prof/epritchard/dqquworf.htm

http://ww2.college-em.qc.ca/prof/epritchard/dqfbques.htm

Present Simple vs Present Continuous

http://www.englishpage.com/verbpage/verbs1.htm

http://www.eclecticenglish.com/grammar/PresentContinuous1F.html

Defining relative clauses

http://www.ego4u.com/en/cram-up/grammar/relative-clauses/exercises?02

http://www.ego4u.com/en/cram-up/grammar/relative-clauses/exercises?10