Columbia Common English Usage Mistakes at GMAT is compiled to help you learn the absolutely essential grammar testing points and avoid the most common mistakes at GMAT to raise your score It has twenty lessons with each one having the following outstanding features: 1. ERROR EXAMPLES: show you what kinds of mistakes most often made at GMAT and how to correct them; 2. GRAMMAR GUIDES: teach you the grammar rules absolutely essential to raise your GMAT score; 3. PRACTICE TESTS: Use sample Sentence Correction and Sentence Completion questions to test your grammar power and readiness for the real GMAT; 4. ANSWER KEYS: provide answers and explanations to help you avoid the mistakes forever to score higher on the GMAT Columbia Common English Usage Mistakes at GMAT is your grammar Bible With the help of our fun and effective way to learn all the essential grammar testing points, you will be able to score higher on the GMAT guaranteed