Prerequisites: English course in high school, some English lectures, 2 scientific papers in quite simple (technical) English written gelengentliche conversations with English-speaking colleagues and fellow students.
I describe my self as English for everyday use, but by no means perfect.
Result: 107/120 pts although I had a much worse feeling..
This book is good to set the mood and preparation, all the parts are well explained, exercise parts and models, and 3 tests are included.
The Kaplan book again contains 4 tests, corresponding to the degree of difficulty in proper test rather. The tests in this book are easier in my eyes, so that one is startled at Kaplan.
So my tip: Start with this book, do the fine-tuning a few days before the test with Kaplan.
Even people who do their English skills are very safe, should advance at least. Once expose a sample test to get used to the pressure of time and the line of questioning.
