Ex. Simple Past-Present Perfect

Excercises on line
Simple Past-Present Perfect

http://web2.uvcs.uvic.ca/elc/studyzone/410/grammar/ppvpast.htm
http://www.englishpage.com/verbpage/verbs5.htm
http://www.ego4u.com/en/cram-up/grammar/simpas-preper
http://www.englisch-hilfen.de/en/exercises/tenses/simple_past_present_perfect.htm
http://www.better-english.com/grammar/pspp1.htm