Present Perfect (since, for, yet, already)

Some links to work on present perfect plus time expressions "already, yet":

http://www.vitutor.com/gramatica_inglesa/verb_tense/present_perfect_ej11.html

http://www.adelescorner.org/grammar/pres_perfect/pres_perfect_yet.html


Present perfect + since, for

http://www.eclecticenglish.com/grammar/PresentPerfect1D.html

http://www.englishexercises.org/makeagame/viewgame.asp?id=5876

http://www.grammarbank.com/since-vs-for-exercises.html


All mixed:

http://baladre.info/english/sedaviwebfront/preperfwords.htm

http://www.montsemorales.com/gramatica/PresPerfpartic.htm


Leave me a comment! Good luck!