I have been an A+-average-student in every class I have ever taken. I always get at least 98% on tests and other assignments. However, just yesterday, I got a 93, which is an A-, on my history test after photoreading all the notes and a chapter in the textbook. I don't know why, but this A- really worries me. I think I should go back to my original system of study.
Could you offer any reasonable explanation of my getting an A- in a subject in which I have always got A+?
