dan i noć

1. day and night; around the clock
   Radio je dan i noć da završi kuću. — He worked day and night to finish the house.
   Ova apoteka radi dan i noć. — This pharmacy is open around the clock.
2. (in kao dan i noć) like night and day
   Ta dva brata su kao dan i noć. — Those two brothers are like night and day.