“洞若观火”与“了如指掌”都有“对情况清楚、明白”的意思,运用时易混淆。前者中的“洞”是“透彻”的意思,偏重在对事理观察彻底。如:①以过去和现在的铁铸一般的事实来测将来,洞若观火!(鲁迅《南腔北调集〈守常全集〉题记》)“洞若观火”在句子中可直接作定语。如:②此外如战时的外交计划也推动得同样迂缓,我们在这次的抗战上多多需要国际友人的 “Cave if the concept of fire ” and “well aware” “Have ” The situation is clear, understand “meaning, easy to confuse. The former ”hole“ is ”thorough “ meaning, emphasis on the thorough observation of the affairs. Such as: ① with the past and present iron cast general facts to measure the future, hole if the concept of fire! (Lu Xun, ”Southern Chamber settled