present perfect asix

http://www.ego4u.com/en/cram-up/grammar/present-perfect-simple/exercises?02
http://www.english-grammar-lessons.com/presentperfectorpastsimple/exercise1.swf

http://www.englishexercises.org/makeagame/viewgame.asp?id=1625
http://www.englishgrammarsecrets.com/presentperfectorpastsimple/exercise4.swf
http://www.english-grammar-lessons.com/presentperfect/exercise2.swf
http://www.english-4u.de/pres_perf_ex4.htm