Grammar

Simple present
http://www.englishpage.com/verbpage/simplepresent.html
Exercises
http://web2.uvcs.uvic.ca/elc/StudyZone/330/grammar/pres1.htm
http://www.learnenglish.de/Games/Tenses/SimplePres.htm
http://www.englisch-hilfen.de/en/complex_tests/simple_present1/index.php


Simple past
http://www.englisch-hilfen.de/en/grammar/sim_past.htm
Exercises
http://www.englisch-hilfen.de/en/complex_tests/simple_past1/index.php
http://www.englishclub.com/grammar/verb-tenses_past_quiz.htm
http://www.learnenglish.de/Games/Tenses/SimplePast.htm

Irregular verbs list
http://www2.gsu.edu/~wwwesl/egw/verbs.htm

 
Present perfect
http://www.englishpage.com/verbpage/presentperfect.html
http://www.englishclub.com/grammar/verb-tenses_present-perfect_s.htm
http://www.isabelperez.com/happy/tenses/pres_perfect.htm

Exercises
http://www.ego4u.com/en/cram-up/grammar/present-perfect-simple/exercises?04
http://www.ego4u.com/en/cram-up/grammar/present-perfect-simple/exercises?05
http://www.ego4u.com/en/cram-up/grammar/present-perfect-simple/exercises?07
http://www.ego4u.com/en/cram-up/tests/present-perfect-simple-3
http://www.ego4u.com/en/cram-up/tests/present-perfect-simple-2


Present progressive
http://www.englishpage.com/verbpage/presentcontinuous.html
Exercises
http://www.englishlearner.com/tests/present_simple_continuous_quiz_1.shtml
http://www.ego4u.com/en/cram-up/grammar/present-progressive/form/exercises?form02


Simple past Vs present perfect

http://web2.uvcs.uvic.ca/elc/StudyZone/410/grammar/ppvpast.htm
http://www.eflnet.com/grammar/presperf1.php
http://www.english-zone.com/verbs/prsperf4.html
http://www.usingenglish.com/quizzes/228.html
http://a4esl.org/q/f/z/zz29bms.htm
http://www.englishpage.com/verbpage/verbs5.htm
http://www.englishpage.com/verbpage/verbs6.htm


Passive voice


http://www.englishclub.com/grammar/verbs-voice_passive.htm


http://www.englishclub.com/grammar/verbs-voice_quiz.htm
http://www.eslgo.com/quizzes/raiderspassive.html
http://www.esc.edu/htmlpages/writerold/pandg/exg13.shtml
http://www.ego4u.com/en/cram-up/tests/hadrians-wall