Hi barnaeva,
With the time that you have remaining before Test Day, you don't really have enough time to properly master any new concepts, but you might still be able to make some adjustments to how you handle the Exam overall.
After taking each CAT, it's important to do a full review of your performance (with the goal of defining WHY you got questions wrong). While a full Mistake Tracker would provide more detail, there are some basic questions that you should look to answer after you take each CAT (and the more specific you can be with your answers, the better).
After reviewing each section of your last
MGMAT CAT, how many questions did you get wrong....
1) Because of a silly/little mistake?
2) Because there was some math/verbal that you just could not remember how to do?
3) Because the question was too hard?
4) Because you were low on time and had to guess?
5) In the Verbal section, how many questions did you "narrow down to 2 choices" but still get wrong?
With the answers to the above questions, you can put in some extra time into the areas that impact your performance the most.
GMAT assassins aren't born, they're made,
Rich