Some GDZ sites have typos. Always cross-reference with the rules in the back of your book.
Complete the exercise first, then use GDZ to check your punctuation or spelling. Some GDZ sites have typos
Look for GDZ versions that include explanations of rules, not just the answers. Some GDZ sites have typos
Which or topic (e.g., participles, complex sentences) are you working on right now? Are you prepping for a specific test or the OGE ? Some GDZ sites have typos