Bas Aarts 
Oxford Modern English Grammar [PDF ebook] 

Oxford Modern English Grammar is Oxford’s brand new and definitive guide to English grammar. This book has been written by a leading expert in the field, covers both British and American English, and makes use of authentic spoken and written examples. Arranged in four clear parts for ease of use, its comprehensive coverage ranges from the very basic to the most complex aspects of grammar, all of which are explained clearly yet authoritatively. This descriptive source of reference is invaluable for those with an interest in the English language, undergraduate and postgraduate students, and for anyone who would like a clear guide to English grammar and how it is used.