Assume you took a math class at the university and didn't ask any questions during the lectures. Now, during the semester break, when your exam is also taking place, you are studying from a script that the professor gradually wrote during the lectures. You relied on this script and did not take many of your own notes, especially for a certain part of the script.
Now, you realize one week before the exam that you have a question about this specific part of the script. It's more a minor question about a definition. But it has significant implications for other aspects of the material.
Is it appropriate to ask the professor a question one week before the exam?
From the professor's perspective, it might give the impression that you weren't fully attentive during the lectures. Also he is a kind of a person that gets angry if you waste his time.