Hi Larbi,
The way that you phrased your answers to my questions makes it sound as if you were trying to answer those questions 'from memory' - and that's not the type of review I'm talking about. A CAT is really a 'measuring device' - when used correctly, it will give you a realistic score and help define your strengths and weaknesses, but it will NOT help you to fix any of those weaknesses. To raise your scores, you have to learn the necessary Tactics and put in the proper practice and repetitions. To that end, you have to define WHY you're getting questions wrong (is it a 'content'/knowledge issue? a Tactical one? Are you making lots of organizational mistakes? etc.) - and the more detailed you can be with that analysis, the better. As such, reviewing each CAT that you take - question by question - is a really important step in your improvement.
Between the Quant and Verbal sections, there are only 67 total questions (and some of them are 'experimental', meaning that they do NOT count towards your score). From what you describe, you're missing 10% of the questions because of little mistakes - and potentially a lot more are lost because you can narrow a Verbal question down to 2 choices but you don't have a clear Tactic for what to do NEXT. Thankfully, these are all issues that you can be improved on, but you might need to invest in Course-oriented materials if you want to make those improvements in just 8 weeks.
GMAT assassins aren't born, they're made,
Rich