puzzle over something
phrasal verb with puzzle verb [ I + adv/prep, T ] uk/ˈpʌz.əl/ us/ˈpʌz.əl/
为…绞尽脑汁，苦思冥想
to try to solve a problem or understand a situation by thinking carefully about it
Scientists are puzzling over the results of the research on the drug. 科学家们在仔细思考这种药的研究结果。