These books are truly Useful if you need to prepare the CPE. I highly recommend the 3 of em. The book 'Common Mistakes at Proficiency' is Organised into sections (or Units) dealing with topics specif. There are exercises to practice Each unit and finally for Assessment Tests to the over-whole understanding. Answer keys are available to enable qui highlight your pain-points. Likewise, 'Objective Proficiency Workbook' has-been of help Tremendous, For Those Who are we prepaid the exam Their Own.