Word FormationExercise 47 of 91

Almost everyone has experienced an (0) OCCASIONAL (OCCASION) poor night's sleep due to worries, an impending (1) .......... (DEAD), or a sick child. For at least 10 per cent of the adult population, though, insomnia is a chronic and burdensome problem. It is also the most (2) .......... (PREVAIL) of all sleep…