GMAT生字表

well, GMAT english is focus more on usage. There are also quite a lot of GMAT test books available. As GMAT is now all computerized based, you may want to buy a set of CD that has practice tests READY. The format of GMAT quesitons is hard because it very much based on the previous questions you answered. Meaning if you answered an easy question correctly, the computer will choose a harder question from the database, and if you answer that question correctly again, they will give you another harder questions next, and they will give you extra bonus points is you answer the difficult questions correctly. On the other hand, if you even answer the easy questions wrong, then even if you answer the next question correctly, they will give you less credit, or even won't get any credit at all.

But I did find some useful site for your reference. You may also want to try out test books from Barron's, or even official GMAT past questions book for EST.

http://www.english-test.net/gmat/vocabulary/words/004/gmat-test.php

Hope that helps