Okay, Igor.

Next MondayI will have my thesis defense. So I will be able to meet you only on Tuesday. If you want to schedule other days to cover these classes, just let me know.

Tell me more about your experience. Where did you meet this people? What did you talk about? By the way, I've noticed you have gchat, so we can chat if you want to. I'll be online the whole week.

Besides, take a good look at these online exercises if you have time:

http://perso.wanadoo.es/autoenglish/gr.perf.i.htm
http://www.better-english.com/grammar/pspp1.htm
http://www.englisch-hilfen.de/en/exercises/past_pres_perf.htm
http://a4esl.org/q/f/z/zz29bms.htm
http://www.english-zone.com/verbs/prsperf4.html
http://www.ego4u.com/en/cram-up/tests/present-perfect-simple-3

If you manage to do any of those and have doubts, just let me know.

Regards,