To add to what Ahmed said, I'd like to point out how you should game plan your test taking time budget. I mean you have four hours. You won't know every answer and that's okay. If you prepare well enough you will succeed. You should try to take the test in 3 1/2 hours which gives you not only time to review marked questions, which are those that you don't know or are very unsure about, as well as time to simply look at your answers. Sometimes you can breeze through a question that is so apparent that you might simply mark the wrong choice. Don't let those lessons learned happen to you. Now, as Ahmed cautioned, don't try to have more than 10% to 20 % marked for review. Having more than that can distract you during the test because some of the answers kind of prepare for other questions later on in the test and then you set off a chain of non-confidence in your mind. I'll leave you with, your goal is to pass with about 80% and remain confident.