[quote="CakeDesu":9m7tgne7]http://www.guidetojapanese.org/learn/grammar this one is very good have some exercises and explain everything [/quote:9m7tgne7]
This was what got me to pass my Japanese (grammar part of the) class.
[b:9m7tgne7]As long as you care enough[/b:9m7tgne7], this is extremely useful and efficient