EXPERIENCES
ACTIONS AND STATES THAT STARTED IN THE PAST AND STILL CONTINUE: I've had a headache for weeks.
PRESENT RESULTS: I've discovered the source of your problem...
GAMES TO PRACTICE THIS TENSE
http://www.eslgamesworld.com/members/games/grammar/perfectpast/present%20perfect%20hangman.html
http://eslgamesworld.com/members/games/grammar/perfectpast/spin%20wheel%20present%20past%20tenses.html
