Hi lin11,
Assuming that you've taken these CATs under realistic, test-like conditions, you've now scored above 700 on three consecutive CATs. As such, there's some question as to why you're still studying (why haven't you taken the Official GMAT?).
Before I can offer you the specific advice that you're looking for, it would help if you could provide a bit more information on how you've been studying and your goals:
1) How long have you studied?
2) What materials have you used?
3) What is your goal score?
4) When are you planning to take the GMAT?
5) When are you planning to apply to Business School?
When taking a CAT, if your goal is to receive a realistic score result, then you really have to do everything in your power to make each CAT 'experience' match up with what you'll face on Test Day. Taking a CAT repeatedly is NOT a realistic choice, since it almost guarantees seeing repeat questions (which is something that will NOT happen on the Official GMAT).
GMAT assassins aren't born, they're made,
Rich