1. http://web2.uvcs.uvic.ca/courses/elc/studyzone/330/grammar/prperf1.htm
2. http://web2.uvcs.uvic.ca/courses/elc/studyzone/330/grammar/prperf2.htm
3. http://web2.uvcs.uvic.ca/courses/elc/studyzone/330/grammar/upperf1.htm
4. http://web2.uvcs.uvic.ca/courses/elc/studyzone/330/grammar/upperf3.htm
Listening:
http://www.englishgrammarsecrets.com/presentperfectorpastsimple/exercise5.html
http://netgrammar.altec.org/Units/Unit_14/a101c14_301000.html
Crossword:
http://www.englishmedialab.com/crosswords/presentperfectcw/index.html