If you’re trying to improve your grammar on your own

This is the most helpful advanced grammar workbook I’ve found.

Grammar and Language Workbook, Grade 12. New York: Glencoe/McGraw Hill, 1999. Print.
ISBN-10: 0028183126
ISBN-13: 978-0028183121
Paperback: 348 pages
Publisher: Glencoe/McGraw-Hill; 1 edition (September 1, 1999)
Language: English
$9.20 at Amazon.com

Language Arts Grammar & Language Workbook, Grade 12: Teacher’s Annotated Edition
ISBN: 0-02-818311-8
You can usually find used copies of the Teacher’s Edition at Amazon. If you don’t, Google the title of the book and the ISBN number to find used copies elsewhere.

Table of Contents
Handbook of Definitions and Rules

Grade 11 Workbook:
Grammar & Language Workbook, Grade 11, Teacher’s Annotated Edition (Glencoe Literature) [Paperback]
Paperback: 392 pages
Publisher: McGraw-Hill Book Company Ltd (August 1, 1999)
ISBN-10: 0028183010
ISBN-13: 978-0028183015