Education Idioms

Cut class

To not go to class. I cut class last week and went to a movie.

Catch on

To understand something, to learn about something. I was finally able to catch on and understand the math problem.

Crack open a book

To open a book to study. I did not crack open a book during the weekend.

Crack a book

To open a book to study. I did not crack a book until the last week of classes.