Essential English Grammar In Use By Raymond Murphy Best
It is impossible to walk into an English school in Tokyo, Madrid, or São Paulo without seeing a dog-eared copy of Murphy. It has spawned a family: English Grammar in Use (the blue intermediate book for B1-B2 levels) and Advanced Grammar in Use (the green book by Martin Hewings).
Use this if you already know the grammar but want to stay sharp. essential english grammar in use by raymond murphy