Cram: to learn a lot of things in a short time, in preparation for an exam (为应考)临时死记硬背
He's been cramming for his exams all week.
他整个星期都一直在拼命准备应考.

Beforehand: earlier; before sth else happens or is done 预先;事先
two weeks/three days/a few hours beforehand
提前两星期╱三天╱几小时
I wish we'd known about it beforehand.
要是我们预先知道这事就好了.