PRESENT PERFECT SIMPLE + for/since; just; ever; yet/already

TUTORIAL (vídeo):

PRESENT PERFECT SIMPLE: http://www.youtube.com/watch?v=PaTx5Mx2F4Y

ACTIVITIES:

https://www.ego4u.com/en/cram-up/grammar/present-perfect-simple/exercises

http://www.englishpage.com/verbpage/verbs5.htm

(for/since; just; ever; yet/already): http://www.uhu.es/antonia.dominguez/presentperfect.pdf

PAST SIMPLE vs PRESENT PERFECT:

http://www.perfect-english-grammar.com/support-files/present_perfect_or_past_simple_2.pdf