perfect tenses

Perfect Tenses

The three perfect tenses in English are the three verb tenses which show action already completed. (The word perfect literally means "made complete" or "completely done.")

They are formed by the appropriate tense of the verb to have plus the past participle of the verb.

Present Perfect: I have seen it. 
(Present tense of to have plus participle. Action is completed with respect to the present.)
Past Perfect: I had seen it. 
(Past tense of to have plus participle. Action is completed with respect to the past.)
Future Perfect: I will have seen it. 
(Future tense of to have plus participle. Action is completed with respect to the future.)

present perfect:
http://web2.uvcs.uvic.ca/elc/studyzone/330/grammar/prperf1.htm
http://www.englisch-hilfen.de/en/exercises/tenses/present_perfect_statements.htm
http://www.ego4u.com/en/cram-up/grammar/present-perfect-simple
http://www.englishpage.com/verbpage/presentperfect.html
http://www.perfect-english-grammar.com/present-perfect-exercises.html
http://www.really-learn-english.com/present-perfect-exercises.html

past perfect:
http://www.really-learn-english.com/past-perfect-exercises.html
http://www.englishgrammarsecrets.com/pastperfect/menu.php
http://www.ego4u.com/en/cram-up/grammar/past-perfect-simple/exercises
http://www.englisch-hilfen.de/en/exercises/tenses/past_perfect_simple_past.htm
http://www.perfect-english-grammar.com/past-perfect-exercise-1.html
http://www.englishpage.com/verbpage/pastperfect.html

future perfect:
http://www.really-learn-english.com/future-perfect-exercises.html
http://www.englisch-hilfen.de/en/exercises/tenses/future_perfect_statements.htm
http://www.perfect-english-grammar.com/future-perfect-exercise-4.html
http://www.englishpage.com/verbpage/futureperfect.html
http://www.learnenglishfeelgood.com/esl-future-perfect-tense2.html
http://www.myenglishpages.com/site_php_files/grammar-exercise-future-perfect.php#.U7IcWRbIQWY