肝心な2年生で習う学習範囲は、1年生の時よりも当然難易度が上がっている。
習う: to take lessons in; to be taught; to learn (from a teacher); to study (under a teacher); to get training in.
学習: study; learning; tutorial.
I am confused about how to read 肝心な2年生で習う学習範囲は, does it mean "the scope of learning that we study in the second grade is crucial"?
Thank you for your kind guidance.