The first two years you’ll be...
The first two years you’ll be exposed to a tremendous amount of stuff from across the curriculum. After that, you’d better prepare for an extensive two years in your subject before comprehensive examinations in your final semester. Even if you’ve aced the other courses, they will turn you away if you don’t show proficiency in comps. In math, you have to answer random and difficult questions in longhand mathematics. In English, you have to pretty much have mastered a work of literature from every period in the language’s history. All of that in addition to the pressure.