PRESENT PERFECT

Here you have some links for further practice on Present Perfect:

AFFIRMATIVE

http://www.englisch-hilfen.de/en/exercises/tenses/present_perfect_statements.htm
http://www.ego4u.com/en/cram-up/grammar/present-perfect-simple/exercises
http://www.really-learn-english.com/present-perfect-exercises.html#01

INTERROGATIVE

www.englishexercises.org/makeagame/viewgame.asp?id=5234
http://www.ego4u.com/en/cram-up/grammar/present-perfect-simple/exercises?08
http://www.englisch-hilfen.de/en/exercises/questions/present_perfect.htm

NEGATIVE
http://www.ego4u.com/en/cram-up/grammar/present-perfect-simple/exercises?05
http://www.englisch-hilfen.de/en/exercises/tenses/present_perfect_negation.htm

YET/JUST/ALREADY
http://www.esl-lounge.com/student/grammar/2g7-just-yet-already.php
http://www.servator.cat/eva/index_files/Grammar/2ndcycle/4tESO/prsperf2.htm
http://eslzone1.tripod.com/grammarinter/_yet.htm