propedeutico ejercicio 2. abril 18th simple and progressive present exercises

http://www.tolearnenglish.com/exercises/exercise-english-2/exercise-english-5033.php

http://www.englisch-hilfen.de/en/exercises/tenses/simple_present_progressive.htm

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

http://web2.uvcs.uvic.ca/elc/studyzone/330/grammar/simcon.htm

http://www.eclecticenglish.com/grammar/PresentContinuous1I.html