Grammar Exercises: Site One
This blog, http://blogs.newsobserver.com/grammar/home, has a series of quizzes, called “Grammar Guide Quiz,” which have multiple choice exercises aimed at clearing up common misunderstandings, mainly semantic, such as the difference between “reign” and “rein” and “loath” and “loathe.” It’s superficial, quick, but I found that there were certain usages which I was not clear on, and it felt good to clear them up.
Great site !