Ф-33

ПОЧЁМ ФУНТ ЛИХА узнать, знать, понять и т. п. coll subord clause Invar fixed WO

(to know, learn) what severe hardship is (by personally experiencing an ordeal, hard time etc): what real trouble (misfortune, suffering, misery etc) is

what hard times are (really like (all about)).

«Жена воспитывалась в детском доме. Сирота... Она с детства узнала, почём фунт лиха стоит...» (Шолохов 1). "My wife had been brought up in a children's home. She was an orphan. .. .She had known what real trouble was since she was a kid" (lc).