We went with "the professional you are going to work with (whatever the title was for that evaluation) wants to learn more about how you learn so she/he will have questions, novel learning activities, and academic tasks for you to do. Have fun but at the same time take it seriously so that we can best help you get the things you need for your education."
I think I also mentioned the there will be questions/tasks that are easy, just right and too hard that you aren't expected to know...that is just how it is set up. The professional might not be able to give you feed back on the questions so don't worry about it. But don't give up because you might know that you got one, struggle with three more but then know the next one...you never know when there will be another one you know so just keep working hard and don't take any of it personally you aren't supposed to know it all and it "ain't over until it is over" and you can't predict exactly when that end is.
Then I mentioned not to be afraid to ask for breaks in between tasks as needed because once you start a task you can't stop to go to the bathroom or rest a bit or even if you just need a break to chat (he is a talker).
