What are your favourite grammar bites resources?? For exercising and checking rules?
I am fond of Cambridge Dictionary Online, Blue Grammar Book, Longman Free Exercises, Perfect English Grammar, AgendaWeb, British Council.
Besides there are amazing courses on English Grammar on Coursera, FutureLearn, edX.
Moreover, I am crazy about some apps, even simple ones, like Duolingo.
What's more, I do love cramming books, some good exercise books like Grammar in Use can be efficient.