Interactive Grammar Practice Sites
Follow the links to find interactive quizzes on a variety of writing and grammar topics.
Capital Community College
Scroll down to Structural Flaws, Punctuation, Stylistic and Confusables. A treasure trove of exercises! A Must!
A good mix of exercises.
English Grammar Connection
The advanced tests aren't that difficult, but they address some mistakes that are easy to make under pressure.
Non Stop English
You can take a variety of quizes with different difficulty levels.
There are not that many quizzes, but the Common Errors should be done even though it is listed as easy.
The Blue Book
A good selection of online quizzes.
Houghton Mifflin College Level Review
Excellent review exercises.
OWL at Purdue
Purdue Univerisity's Writing Center
Writing and Grammar exercises