English Grammar Online

http://www.ego4u.com/en/cram-up/grammar

Great site with excellent explanations, quizzes, reading texts using the verb tense, and contrasts with commonly confused verb tenses.

 

University of Victoria, Study Zone Grammar Page

Grammar Index | Continuing Studies at UVic

One of my personal favorite sites.  Has great explanations for each topic, followed by two different exercises

 

English Page

http://www.englishpage.com/verbpage/verbtenseintro.html

Great explanations and tense contrast exercises.

 

GrammarQuizzes.com

http://www.grammar-quizzes.com/index.html

Great site with verb tenses, clauses, articles, conditionals, etc.  The explanations are long and complete, with lots of exercises at the end.

 

Road to Grammar

http://www.roadtogrammar.com/welcome/

Very extensive lists of grammar topics with quizzes.  If you click the "notes" section, there's a nice, concise explanation for the topic.

 

Daily Grammar

http://www.dailygrammar.com/archive.html

This site has very short (as in 1-3 sentences) explanations anda then a short exercise.  But it has every single grammar topic imagineable!

 

EduFind Grammar

http://www.edufind.com/english/grammar/grammar_topics.php

This site has a very extensive list of grammar topics.  Each one has a nice, concise explanation with lots of examples.  You have to click over to their test section to get quizzes for the topic.

 

ESL Classroom

http://www.esl-classroom.com/grammar/gindex.html

There are no explanations here, and the site only has prepositions, perfect tenses, and passive.  But it also has a section on error recognition in sentences--nice for editing practice.

 

English Pond

http://www.englishpond.com/index.html

The information in this site is a little limited, but the games in the lower part of each page are really nice, particularly the grammar and vocabulary pages.

 

5-Minute English

http://www.5minuteenglish.com/grammar.htm

These are quite short grammar explanations, but without exercises.  The site is good for a student who needs just a little bit more explanation.