useful websites to practice present perfect tense

http://www.perfect-english-grammar.com/past-simple-present-perfect-1.html

http://www.perfect-english-grammar.com/past-simple-present-perfect-2.html

http://www.usingenglish.com/quizzes/228.html

http://www.vipingilizce.com/present-perfect-tense-exercises-quiz/

http://web2.uvcs.uvic.ca/elc/studyzone/330/grammar/prperf1.htm

http://www.englisch-hilfen.de/en/complex_tests/simple_past_present_perfect1/index.php