If you are a serious student of English grammar, I can recommend: A Student's Introduction to English Grammar. By Rodney Huddleston & Geoffrey K. Pullum Published by Cambridge University Press ISBN: 978-0-521-61288-3 Here's a link: http://www.cambridge.org/gb/academic/subjects/languages-linguistics/grammar-and-syntax/students-introduction-english-grammar You can buy it on the Cambridge website for about GBP22. PaulM