PRESENT SIMPLE, PRESENT CONTINUOUS:
http://www.englishexercises.org/makeagame/viewgame.asp?id=1438
http://www.usingenglish.com/quizzes/66.html
PAST SIMPLE:
http://www.curso-ingles.com/ejercicios-test-ingles/pasado.php
http://english-quiz.net/past-simple-tense-quiz.html
http://www.learnenglishfeelgood.com/simple-past-tense3.html
PAST SIMPLE, PAST CONTINUOUS:
http://www.eslmania.com/students/grammar/Grammar_Quizzes/past_continuous_tense.htm
http://www.learnenglish-online.com/grammar/tests/pastcontinuoussimplepast.html
PRESENT PERFECT:
http://www.ecenglish.com/learnenglish/lessons/present-perfect-quiz
http://a4esl.org/q/f/z/zz29bms.htm
http://www.eslcafe.com/quiz/past2.html
