Фразовые глаголы: CRACK

CRACK DOWN - to be more severe in the enforcement of a punishment or of a rule.
The police are cracking down on underage drinking.

CRACK UP - to become depressed, under pressure or anxious.
She cracked up because of the pressure of her new job.

ALSO
CRACK UP - to laugh because something is very funny.
That movie cracked me up.

CRACKED UP TO BE - supposed to be, expected.
Hes cracked up to be the greatest pitcher of all time.