Cram up meaning

cram verb (LEARN) ... She's cramming for her history exam. 為應付歷史考試她拼命突擊。

Your example lacks context. Where are the people crammed? Without knowing more, I would say that ...

1 verb If you cram things or people into a container or place, you put them into it, although the...

1 · to pack tight : jam cram a suitcase with clothes ; 3 · to thrust in or as if in a rough or fo...