She spent the day fretting about/over what she'd said to Nicky.她为对尼基说的话而担心了一整天。
fret
noun[ C ]uk/fret/us/fret/
(吉他等弦乐器指板上定音的)品
any of the small raised metal bars across the long, thin part of a stringed musical instrument such as a guitar, that show you where to put your fingers on the strings in order to produce different notes